I85PREP
⌘ K
UPMSP Vocational Crop Protection Technology study materials
UPMSP Vocational Crop Protection Technology study resources

UPMSP Vocational Crop Protection Technology practice questions

One question at a time. Build your UPMSP Vocational Crop Protection Technology understanding.

First 50 of 200 questions. Each one lists the choices, the correct answer, and an explanation. The checker at the top of this page saves progress in this browser when it is available.

Continue in the practice tool above to load more questions, 50 at a time.

Question 1Crop Protection Fundamentals and Integrated Pest Management

In integrated pest management, which practice is classified as a cultural control method for reducing insect pest populations in a crop field?

  1. Adjusting sowing dates to avoid peak pest emergence Correct answer.
  2. Releasing Trichogramma egg parasitoids into the field
  3. Applying a systemic fungicide as a seed treatment
  4. Spraying a broad-spectrum organophosphate on a calendar schedule

Explanation

Cultural control manipulates normal farming operations such as sowing time, crop rotation, spacing, and sanitation so that the crop escapes or resists pest attack. Adjusting sowing dates to avoid peak pest emergence is a classic cultural method because it disrupts synchrony between the pest and its host. The other options involve chemical or biological inputs rather than crop management practices.

Question 2Crop Protection Fundamentals and Integrated Pest Management

The economic threshold level (ETL) in pest management is best described as which of the following?

  1. The pest density at which control measures should be initiated to prevent the population from reaching the economic injury level Correct answer.
  2. The pest density at which a pesticide application always gives a profitable return
  3. The maximum pest population that a crop can tolerate without any measurable yield loss
  4. The total number of insecticide sprays permitted in one cropping season

Explanation

The ETL is the pest density at which control action should begin, set slightly below the economic injury level so that intervention occurs before losses exceed control costs. It is an action trigger, not a tolerance ceiling or a spray count. This distinction guides judicious pesticide use within IPM.

Question 3Crop Protection Fundamentals and Integrated Pest Management

A farmer finds aphids colonising the undersides of leaves with a few alate (winged) forms appearing. Which monitoring interpretation is most appropriate for IPM decision-making?

  1. The crop should be sprayed immediately because a single aphid always exceeds the ETL
  2. Winged aphids indicate the colony is dying out and no action is needed
  3. Aphids on leaf undersides never cause economic damage and can be ignored
  4. The presence of winged aphids suggests the colony is crowded and spread to new plants is likely, so field-wide scouting should be intensified Correct answer.

Explanation

Winged morphs are produced when colonies become crowded or host quality declines, and they disperse to colonise new plants, so their appearance signals likely spread. Intensifying scouting across the field allows a density estimate against the ETL before deciding on control. A single aphid or a local colony does not by itself justify spraying.

Question 4Crop Protection Fundamentals and Integrated Pest Management

Which statement correctly distinguishes an insecticide's contact action from its systemic action?

  1. Systemic insecticides work only on soil-dwelling pests, while contact insecticides work only on foliage
  2. A contact insecticide is absorbed by roots and moved upward, whereas a systemic insecticide only kills pests touched by spray droplets
  3. Contact insecticides persist longer inside plant sap than systemic insecticides do
  4. A contact insecticide acts on pests hit by spray deposits, whereas a systemic insecticide is absorbed and translocated within plant tissue to act on pests feeding there Correct answer.

Explanation

Contact insecticides kill pests that are directly wetted by the spray deposit and offer little protection to insects hidden in sheltered feeding sites. Systemic insecticides are taken up by the plant and translocated in the sap, so sap-feeding pests such as aphids and leafhoppers are exposed even when not directly sprayed. This difference guides product choice according to pest feeding behaviour.

Question 5Crop Protection Fundamentals and Integrated Pest Management

In an IPM programme, rotating insecticide groups with different modes of action according to IRAC classification is done primarily to achieve which outcome?

  1. Delay the selection of resistant pest populations Correct answer.
  2. Eliminate the need for scouting
  3. Make the products toxic to natural enemies
  4. Increase the residual life of each product

Explanation

Repeated use of one mode of action selects resistant individuals, so rotating among IRAC groups exposes the population to different toxic mechanisms and slows resistance development. Rotation is a resistance management tactic, not a way to extend residue life or replace monitoring. Preserving natural enemies is a separate consideration that argues for selective products.

Question 6Crop Protection Fundamentals and Integrated Pest Management

A scout uses a sweep net across a rice field and records 40 hoppers per 50 sweeps, while the locally recommended ETL is 60 hoppers per 50 sweeps. What is the most defensible IPM decision?

  1. Record the count, continue monitoring at intervals, and hold off on insecticide until the threshold is approached Correct answer.
  2. Apply insecticide immediately because any hopper presence justifies treatment
  3. Double the insecticide dose to prevent the population from rising
  4. Stop scouting for the season because the population is below threshold

Explanation

When the sampled density is below the recommended ETL, the correct IPM response is to keep monitoring so that action can be taken if the population rises toward the threshold. This avoids unnecessary sprays that disrupt natural enemies and promote resistance. Immediate treatment or dose escalation is not justified by a sub-threshold count.

Question 7Crop Protection Fundamentals and Integrated Pest Management

Which feature is characteristic of a virus disease symptom on a crop plant, as distinguished from most fungal leaf spot diseases?

  1. Mosaic mottling and distortion that are systemic and not controlled by fungicides Correct answer.
  2. Circular necrotic spots with concentric rings and fungal fruiting bodies
  3. Water-soaked lesions that ooze bacterial slime when cut
  4. White powdery growth confined to the upper leaf surface

Explanation

Viral infections commonly cause systemic symptoms such as mosaic mottling, vein clearing, stunting, and leaf distortion, and they cannot be cured with fungicides. Diagnosis therefore relies on symptom pattern, vector control, and resistant varieties. The other descriptions fit fungal or bacterial pathogens.

Question 8Crop Protection Fundamentals and Integrated Pest Management

In fungal disease epidemiology, which condition most favours an outbreak of a downy mildew in a field crop?

  1. Dry, hot afternoons with low humidity and strong wind
  2. Prolonged leaf wetness with high humidity and moderate temperatures Correct answer.
  3. Very low humidity with cool nights and no dew
  4. Deep ploughing followed by a long dry spell

Explanation

Downy mildew pathogens depend on free moisture and high humidity for spore germination and infection, and moderate temperatures favour their development. Prolonged leaf wetness therefore drives epidemic build-up. Dry, low-humidity conditions suppress spore germination and limit spread.

Question 9Crop Protection Fundamentals and Integrated Pest Management

Which method is an example of biological control of a plant pathogen rather than of an insect pest?

  1. Release of Chrysoperla larvae to feed on aphids
  2. Seed treatment with a antagonistic Trichoderma formulation that suppresses soil-borne pathogens Correct answer.
  3. Setting up yellow sticky traps to catch whiteflies
  4. Application of Bacillus thuringiensis kurstaki against caterpillar larvae

Explanation

Biological control of pathogens uses antagonistic microorganisms that compete with, parasitise, or inhibit the pathogen, and Trichoderma formulations applied to seed or soil are a standard example. The other options target insect pests through predation, microbial insecticide, or trapping. Recognising the target organism is essential for correct classification.

Question 10Crop Protection Fundamentals and Integrated Pest Management

A grower notices that a herbicide that previously controlled a weed species well now leaves many survivors that set seed. Which management response best fits integrated weed management?

  1. Abandon herbicide use entirely and rely on a single tillage pass
  2. Increase the dose of the same herbicide every season until control returns
  3. Apply the same herbicide twice as often within the season
  4. Integrate cultural and mechanical tactics with herbicides from different mode-of-action groups and prevent weed seed set Correct answer.

Explanation

Survivors that set seed indicate selection for resistance, and the integrated response is to diversify tactics, rotate herbicide modes of action, and stop seed production to reduce the seed bank. Simply escalating dose or frequency intensifies selection pressure and is unsustainable. Abandoning all herbicide without an effective alternative can also fail.

Question 11Crop Protection Fundamentals and Integrated Pest Management

Which statement best describes the role of a pheromone trap in IPM?

  1. It provides nutrition to the crop to increase tolerance to pests
  2. It sterilises the soil against soil-borne pathogens
  3. It uses a synthetic sex attractant to monitor adult pest activity and time interventions Correct answer.
  4. It kills all insects that enter the field regardless of species

Explanation

Pheromone traps use synthetic versions of species-specific sex attractants to detect and monitor adult flights, which helps time scouting and control operations. Because the lure is species-specific, it does not act as a general insect killer. Traps can also support mass trapping or mating disruption in some programmes.

Question 12Crop Protection Fundamentals and Integrated Pest Management

Which of the following is the most important reason for conserving natural enemies such as ladybird beetles and parasitic wasps in an IPM programme?

  1. They make the crop immune to all diseases
  2. They suppress pest populations and can reduce the frequency of insecticide applications Correct answer.
  3. They increase the residual toxicity of applied insecticides
  4. They directly supply nitrogen to the crop through their feeding

Explanation

Natural enemies exert continuous mortality on pest populations, and conserving them can keep pests below the ETL and reduce reliance on insecticides. This is why selective products and threshold-based spraying are favoured in IPM. They do not fertilise the crop, confer disease immunity, or enhance pesticide residues.

Question 13Crop Protection Fundamentals and Integrated Pest Management

A seed lot shows dark discolouration and the laboratory reports seed-borne infection. Which principle of plant disease management does hot-water seed treatment primarily apply?

  1. Raising the economic injury level of the pathogen
  2. Attracting vectors that spread the pathogen
  3. Eliminating or reducing primary inoculum carried on or in the seed Correct answer.
  4. Increasing the susceptibility of the seedling to infection

Explanation

Hot-water treatment uses a temperature and time regime that kills pathogen propagules carried on or within the seed while preserving viability, thereby reducing primary inoculum at the start of the season. This is a physical therapy targeted at seed-borne infection. It does not alter host susceptibility, thresholds, or vectors in the intended direction.

Question 14Crop Protection Fundamentals and Integrated Pest Management

Which pair correctly matches a pesticide formulation type with a practical property relevant to field use?

  1. Wettable powder (WP) - dissolves completely to give a true solution
  2. Dust (D) - is diluted with water before application
  3. Emulsifiable concentrate (EC) - forms an emulsion on dilution with water and often contains organic solvent Correct answer.
  4. Granule (G) - is applied as a fine spray through hydraulic nozzles

Explanation

An emulsifiable concentrate is a liquid formulation that, on dilution with water, forms an emulsion and typically contains organic solvents and emulsifiers. Wettable powders form suspensions rather than true solutions, granules are applied dry as particles, and dusts are applied dry without dilution. Matching formulation to its behaviour helps avoid application errors.

Question 15Crop Protection Fundamentals and Integrated Pest Management

A farmer wants to reduce the risk of pesticide resistance in a fungal pathogen population. Which practice is most consistent with anti-resistance guidelines?

  1. Alternate or mix fungicides with different modes of action and limit the number of applications per season Correct answer.
  2. Apply the same single-site fungicide repeatedly throughout the season
  3. Use half the recommended dose to reduce selection pressure
  4. Spray only when the crop shows severe disease symptoms

Explanation

Fungicide resistance management relies on diversifying modes of action, respecting label limits on application number, and using mixtures or alternations with multi-site partners. Repeated use of a single-site product selects resistant strains rapidly. Reduced doses can be even riskier because they expose the pathogen to sub-lethal concentrations.

Question 16Crop Protection Fundamentals and Integrated Pest Management

Which symptom pattern most strongly suggests a bacterial rather than a fungal cause of a leaf disease?

  1. Cottony mycelium with spore-bearing structures on the underside
  2. Angular water-soaked lesions delimited by veins that exude bacterial ooze in water Correct answer.
  3. Concentric rings of dead tissue with raised fungal bodies
  4. Powdery white growth on the leaf surface

Explanation

Bacterial leaf lesions are often angular because the bacteria are limited by veins, and they may exude ooze when cut and placed in water. These features reflect bacterial multiplication and movement in intercellular spaces. Powdery growth, concentric rings, and cottony mycelium are fungal signs.

Question 17Crop Protection Fundamentals and Integrated Pest Management

Which of the following best describes the principle of crop rotation as a pest and disease management tool?

  1. Growing a non-host crop in sequence deprives host-specific pathogens and pests of their food source and reduces inoculum build-up Correct answer.
  2. Rotating crops increases the host range of specialist pathogens
  3. Rotating crops eliminates the need for any other control measure
  4. Growing the same crop every year builds resistance in the soil

Explanation

Rotation interrupts the life cycle of host-specific pathogens and pests by removing their host for one or more seasons, which reduces survival structures and population build-up. It is most effective against organisms with limited host ranges and short survival. Rotation is a component of IPM, not a replacement for all other measures.

Question 18Crop Protection Fundamentals and Integrated Pest Management

A crop is infested with a sucking pest and the grower wants to avoid harming pollinators foraging in the field. Which action is most appropriate?

  1. Mix several insecticides to guarantee rapid kill
  2. Apply a broad-spectrum insecticide at midday when flowers are open
  3. Choose a selective product and apply it outside peak foraging hours, following label pollinator warnings Correct answer.
  4. Increase the dose to shorten the residual period

Explanation

Pollinator protection depends on product selectivity and timing applications when pollinators are not actively foraging, together with label instructions. Broad-spectrum sprays during open bloom expose foragers to residues. Increasing dose or tank-mixing products raises hazard without solving the timing problem.

Question 19Crop Protection Fundamentals and Integrated Pest Management

Which statement about the label of a registered pesticide is correct for a crop protection technician?

  1. The label directions, including dose, target pest, waiting period, and safety precautions, are legally binding conditions of use Correct answer.
  2. The label is advisory only and doses can be adjusted freely to local conditions
  3. The waiting period can be shortened if the crop looks healthy
  4. The label applies only to the first application in a season

Explanation

A registered label defines the approved use, including dose, target, pre-harvest interval, and safety measures, and using a product contrary to the label is a legal violation. The pre-harvest interval protects consumers from residues and must be observed for every application. Local adjustment beyond the label is not permitted.

Question 20Crop Protection Fundamentals and Integrated Pest Management

In an IPM programme for a fruit orchard, which combination best represents the correct hierarchy of tactics?

  1. Preventive cultural and sanitation measures first, then monitoring and biological options, with pesticides as a last resort at the ETL Correct answer.
  2. No monitoring, with decisions based on the neighbour's spray schedule
  3. Pesticides applied on a fixed calendar first, with cultural measures only after resistance appears
  4. Biological control used only after all chemical options have failed

Explanation

IPM prioritises prevention through cultural and sanitation practices, then monitoring and biological or other non-chemical tactics, and reserves pesticides for situations where pest density reaches the ETL. This hierarchy reduces reliance on chemicals and slows resistance. Calendar spraying or copying neighbours ignores local pest status.

Question 21Crop Protection Fundamentals and Integrated Pest Management

A laboratory bioassay shows that a field population of a pest survives a dose that previously killed 95 percent of the population. Which conclusion is most defensible?

  1. The ETL has automatically increased
  2. The pest has become a beneficial insect
  3. The pesticide has definitely deteriorated and no resistance exists
  4. The population has likely developed resistance and its response should be compared with a known susceptible reference strain Correct answer.

Explanation

A reduced mortality at a formerly effective dose suggests selection for resistance, and confirmation requires comparing the field population with a susceptible reference strain under the same conditions. This comparison distinguishes true resistance from application or product problems. The ETL and pest status are unrelated to the bioassay result.

Question 22Crop Protection Fundamentals and Integrated Pest Management

A disease epidemic progresses slowly at first, then accelerates rapidly as secondary spread occurs. Which factor most directly explains the rapid phase in a polycyclic disease?

  1. Complete absence of susceptible host tissue
  2. A single infection event with no further spore production
  3. Repeated secondary infection cycles producing many new spores within the season Correct answer.
  4. Failure of spores to disperse from the initial lesion

Explanation

Polycyclic pathogens complete multiple infection cycles per season, so each lesion produces spores that initiate new infections, giving compound epidemic growth. The rapid phase reflects this multiplication and dispersal. Monocyclic pathogens with a single cycle show slower, steadier progress.

Question 23Crop Protection Fundamentals and Integrated Pest Management

A grower plans to use a non-selective herbicide in a field where a sensitive crop is growing nearby. Which precaution is most important to prevent crop injury?

  1. Remove the sprayer filters to increase flow
  2. Spray during strong gusts to disperse the droplets
  3. Apply at the highest label dose to finish quickly
  4. Check wind conditions and use shielded or directed application with appropriate nozzles to prevent spray drift Correct answer.

Explanation

Drift of a non-selective herbicide onto a sensitive crop can cause severe injury, so application must consider wind direction and speed and use shielding or directed spraying to keep the spray on target. Higher doses, windy conditions, and removing filters all increase off-target movement or application error.

Question 24Crop Protection Fundamentals and Integrated Pest Management

An IPM advisor must decide between two control options for a pest at the ETL. Option A costs more but preserves natural enemies and has a longer residual; option B is cheaper but broad-spectrum and kills natural enemies. Which analysis best reflects IPM decision-making?

  1. Compare total season-long costs and benefits, including the risk of secondary pest outbreaks and resistance from option B, not just the immediate price Correct answer.
  2. Defer the decision until the pest population has destroyed the crop
  3. Choose option B solely because it is cheaper at the time of application
  4. Choose option A solely because it is more expensive

Explanation

IPM decisions weigh the full economic and ecological consequences, including the value of conserved natural enemies, the risk of secondary pest outbreaks, and resistance selection, rather than the immediate purchase price. A broad-spectrum option can cost more later through disrupted biocontrol. Deferring action past the ETL allows avoidable loss.

Question 25Crop Protection Fundamentals and Integrated Pest Management

Which explanation best accounts for the failure of a contact insecticide to control a leaf-miner infestation even when applied at the label dose?

  1. Leaf-miners are fungi and are not affected by insecticides
  2. Contact insecticides only work on stored grain pests
  3. The larvae feed inside leaf tissue and are protected from spray deposits, so a translaminar or systemic product or another tactic is needed Correct answer.
  4. The insecticide was applied at the label dose, which always kills all leaf-miners

Explanation

Leaf-miner larvae feed within the leaf between the epidermal layers, where contact spray deposits do not reach them, so control requires translaminar or systemic activity or non-chemical tactics. The label dose is not a guarantee of control when the target is physically protected. Leaf-miners are insects, not fungi.

Question 26Crop Protection Fundamentals and Integrated Pest Management

In integrated pest management, which term describes the pest population density at which control measures should be initiated to prevent the pest from reaching the economic injury level?

  1. Economic injury level
  2. Economic threshold level Correct answer.
  3. Damage boundary
  4. General equilibrium position

Explanation

The economic threshold level is the density at which action must be taken so that the population does not rise to the economic injury level, where losses equal control costs. It is deliberately set below the economic injury level to allow time for the control measure to act. The economic injury level itself is the break-even density, not the trigger point.

Question 27Crop Protection Fundamentals and Integrated Pest Management

A crop protection technician is choosing among control tactics for a soil-borne pathogen that survives for many years in the field as thick-walled resting structures. Which single tactic most directly reduces the amount of this inoculum in the soil?

  1. Spraying a contact fungicide on the foliage
  2. Raising the humidity inside the crop canopy
  3. Applying a sticker-spreader to the seed surface
  4. Growing a non-host crop in a long rotation Correct answer.

Explanation

Long resting structures survive in soil and are reduced mainly by depriving them of a susceptible host, which is what a long rotation with a non-host accomplishes over successive seasons. Foliar sprays do not reach soil-borne resting structures, and canopy humidity or adjuvants do not lower soil inoculum.

Question 28Crop Protection Fundamentals and Integrated Pest Management

A scout reports that a chewing caterpillar has crossed the economic threshold level in a vegetable field, but a parasitic wasp is already attacking a large share of the larvae. Which action best follows the hierarchy of IPM tactics?

  1. Apply the broad-spectrum insecticide immediately at the label dose
  2. Double the insecticide dose to overcome larval survival
  3. Delay all action and wait for the next crop season
  4. Use a selective or biological measure that spares the parasitoid Correct answer.

Explanation

Once the threshold is crossed, action is justified, but IPM requires choosing the tactic least damaging to existing natural control, so a selective or biological option that conserves the parasitoid is preferred. Broad-spectrum sprays at once, or doubling the dose, would destroy the parasitism already suppressing the pest and risk resistance and resurgence.

Question 29Crop Protection Fundamentals and Integrated Pest Management

A farmer rotates between two unrelated crops, yet a soil-borne pathogen still builds up on both crops in the same field. Which explanation best accounts for the failure of this rotation to control the pathogen?

  1. The pathogen survives only inside the seed coat
  2. The rotation was applied for a single growing season
  3. The pathogen has a very wide host range that includes both crops Correct answer.
  4. The pathogen is spread only by wind-blown spores

Explanation

Rotation works by starving a pathogen of susceptible hosts, so it fails when the pathogen can attack both crops in the sequence because of a broad host range. Wind dispersal, a short rotation period, or seed-borne survival are different mechanisms and would not by themselves explain failure on two unrelated crops.

Question 30Crop Protection Fundamentals and Integrated Pest Management

An IPM adviser compares two fields with the same pest and the same crop. In field A the pest has many generations per year and a short life cycle; in field B it has one generation per year and a long life cycle. Assuming both are exposed to the same repeated selection from one insecticide, which field is expected to develop resistance faster, and why?

  1. Field B, because a long life cycle allows more time for mutations to appear
  2. Field A, because more generations per year mean more selection cycles per unit time Correct answer.
  3. Both equally, because resistance depends only on the dose applied
  4. Field B, because univoltine pests are always exposed at the most susceptible stage

Explanation

Resistance evolution depends on the number of generations under selection, so a pest with many short generations passes through more selected cycles each year and accumulates resistance alleles faster. Mutation supply and generation turnover, not calendar time alone or dose by itself, drive the difference.

Question 31Entomology: Insect Pests of Field and Horticultural Crops

Which mouthpart type is characteristic of the rice weevil (Sitophilus oryzae) as an adult?

  1. Siphoning type coiled under the head
  2. Piercing-sucking type with a long proboscis
  3. Chewing type with a short rostrum Correct answer.
  4. Rasping-sucking type with a rasping tongue

Explanation

Weevils are beetles (Coleoptera) whose adults possess chewing mouthparts, modified into a snout-like rostrum that bears the mandibles at its tip. This allows the adult to bore into stored grain and feed on the endosperm. Siphoning and piercing-sucking types belong to Lepidoptera and Hemiptera respectively.

Question 32Entomology: Insect Pests of Field and Horticultural Crops

A farmer finds that the growing tip of a young cotton plant is killed and the plant later produces excessive vegetative branches. Which pest is most likely responsible?

  1. Termites attacking the tap root below soil
  2. Aphids clustered on the underside of leaves
  3. Pink bollworm larvae boring into green bolls
  4. Spotted bollworm larvae feeding inside the terminal shoot Correct answer.

Explanation

Early-instar spotted bollworm (Earias spp.) larvae bore into the growing shoot of cotton and kill the apical bud, a symptom called dead heart. Loss of apical dominance releases lateral buds, producing excessive vegetative branching and delayed fruiting. Boll-boring pests damage the bolls directly and do not cause shoot death.

Question 33Entomology: Insect Pests of Field and Horticultural Crops

The characteristic symptom of brown plant hopper (Nilaparvata lugens) infestation in rice is best described as:

  1. Circular patches of drying plants called hopper burn, with sooty mould Correct answer.
  2. Yellow-orange streaks on leaves with bacterial ooze
  3. Galls on the stem base with stunted tillering
  4. White earheads with empty grains and cut panicle necks

Explanation

Both nymphs and adults of the brown plant hopper suck sap from the basal part of the rice tiller, so plants dry in circular patches known as hopper burn. Honeydew excreted during feeding supports sooty mould growth. The other symptoms listed belong to stem borer, bacterial leaf streak and gall midge respectively.

Question 34Entomology: Insect Pests of Field and Horticultural Crops

Yellow sticky traps placed in a vegetable nursery are used mainly because they attract and catch:

  1. Root-knot nematodes in the soil
  2. Soil-dwelling cutworm larvae
  3. Grub stages of scarab beetles
  4. Whiteflies and other small flying adults Correct answer.

Explanation

Yellow sticky traps exploit the positive response of many small sap-sucking adults, such as whiteflies, aphids and thrips, to yellow wavelengths. They provide early detection and mass trapping of winged adults in nurseries and greenhouses. Crawling larvae, soil nematodes and soil-inhabiting grubs are not captured by aerial traps.

Question 35Entomology: Insect Pests of Field and Horticultural Crops

A field of mustard suddenly shows small, dark, shiny flea beetles riddling the cotyledons and young leaves with shot holes. Which management action gives the fastest reliable control of these adults?

  1. Spraying an approved insecticide on the foliage Correct answer.
  2. Applying farmyard manure before sowing
  3. Releasing Trichogramma egg parasitoids
  4. Deep summer ploughing to bury pupae

Explanation

Adult flea beetles (Phyllotreta spp.) feed on the exposed foliage, so a foliar insecticide directed at the adults acts quickly. Soil cultivation and parasitoid release target other life stages and act too slowly for an active adult outbreak. Manure application has no direct effect on adult beetle populations.

Question 36Entomology: Insect Pests of Field and Horticultural Crops

The sugarcane top borer (Scirpophaga excerptalis) larva in the early stage produces which characteristic symptom?

  1. Reddish rot of the stem with a sour fermented smell
  2. Spongy white tissue in the central shoot with a bunchy top
  3. Bunchy top with short, narrow internodes and a dead heart Correct answer.
  4. Parallel white streaks on the leaf lamina

Explanation

The newly hatched top borer larva enters the midrib and then the growing point, killing it and producing a dead heart. When the shoot regrows, internodes remain short and leaves become narrow and clustered, giving a bunchy top. The combination of dead heart followed by bunchy top is diagnostic.

Question 37Entomology: Insect Pests of Field and Horticultural Crops

Which stage of the fruit fly Bactrocera dorsalis causes economic damage to mango fruits?

  1. The larva tunnelling through the fruit pulp Correct answer.
  2. The pupa resting in the soil under the tree
  3. The egg laid on the fruit surface
  4. The adult fly feeding on leaf sap

Explanation

The female fruit fly inserts eggs under the rind of ripening mango, and the emerging maggots tunnel through the pulp, causing rotting and premature fruit drop. Adults feed on honeydew and fruit exudates but do not tunnel. Pupation occurs in the soil and the egg stage itself causes no tissue damage.

Question 38Entomology: Insect Pests of Field and Horticultural Crops

A pest population in a cotton field has developed resistance to a pyrethroid after repeated sprays. Which strategy best slows further resistance development?

  1. Rotating insecticides with different modes of action Correct answer.
  2. Increasing the dose of the same pyrethroid
  3. Spraying the pyrethroid more frequently
  4. Mixing two products with the same mode of action

Explanation

Resistance management relies on reducing selection pressure by alternating chemical groups that act on different target sites, ideally combined with non-chemical tactics. Increasing dose or frequency strengthens selection for resistant individuals. Mixing products with the same mode of action does not diversify the selection pressure.

Question 39Entomology: Insect Pests of Field and Horticultural Crops

The gurdaspur borer of sugarcane is unusual among the sugarcane borers because its larva:

  1. Feeds only on the growing point of the cane
  2. Bores into the leaf midrib only
  3. Boils down the cane top and tunnels downwards
  4. Attacks the cane from the base and tunnels upwards Correct answer.

Explanation

The gurdaspur borer (Acigona steniellus) enters the cane near the base and tunnels upwards, so the entry hole and frass are seen at the lower internodes. Most other sugarcane borers start at the top or the growing point and move downwards. This upward direction of tunnelling distinguishes it in the field.

Question 40Entomology: Insect Pests of Field and Horticultural Crops

In the sterile insect technique used against fruit flies, control is achieved by releasing:

  1. Parasitised larvae of the target species
  2. Predatory mites that attack pupae
  3. Mass-reared males sterilised by irradiation Correct answer.
  4. Females treated with a chemosterilant bait

Explanation

The sterile insect technique releases large numbers of mass-reared males that have been sterilised, usually by gamma irradiation, so that wild females mate with them and produce no offspring. Repeated releases over several generations collapse the wild population. Predators, baits and parasitoids work by different mechanisms and are not part of the technique.

Question 41Entomology: Insect Pests of Field and Horticultural Crops

Which symptom on okra leaves is most typical of damage by the shoot and fruit borer (Earias vittella)?

  1. Silvery speckling with webbing on the lower surface
  2. Drying of the terminal shoot with a visible entry hole Correct answer.
  3. Sticky honeydew covered by black sooty mould
  4. Circular water-soaked spots with a yellow halo

Explanation

The okra shoot and fruit borer larva bores into the terminal shoot, killing it so that it droops and dries, and an entry hole with frass is visible. Later larvae enter the fruits and make them unfit for market. The other symptoms describe mite, fungal and sap-sucker damage respectively.

Question 42Entomology: Insect Pests of Field and Horticultural Crops

The most important cultural practice for reducing carry-over of pink bollworm from one cotton season to the next is:

  1. Spraying the standing crop with neem oil
  2. Irrigating the field immediately after harvest
  3. Destroying and ploughing in harvested stalks and bolls Correct answer.
  4. Sowing a high-yielding hybrid variety

Explanation

Pink bollworm larvae complete their development in unopened bolls and rosette flowers left on the plant or in gin trash, and pupate in the soil. Prompt destruction of stalks, unharvested bolls and trash after harvest removes this carry-over population. Variety choice, neem sprays and irrigation do not remove the overwintering reservoir.

Question 43Entomology: Insect Pests of Field and Horticultural Crops

A farmer notices shiny, sticky leaves with black fungal growth on citrus, and ants moving along the branches. Which pest group should be investigated first?

  1. Sap-sucking aphids, scales or whiteflies Correct answer.
  2. Fruit-boring moth larvae in the pulp
  3. Leaf-mining larvae inside the lamina
  4. Bark-eating beetle grubs in the trunk

Explanation

Honeydew, sooty mould and ant attendance form a classic syndrome of phloem-feeding Hemiptera such as aphids, soft scales and whiteflies. Ants tend these insects and protect them from natural enemies. Miners, bark beetles and fruit borers do not produce honeydew.

Question 44Entomology: Insect Pests of Field and Horticultural Crops

Which biological control agent is correctly matched with the pest it is used against in field crops?

  1. Bacillus thuringiensis against aphid nymphs
  2. Nuclear polyhedrosis virus against whitefly adults
  3. Beauveria bassiana against rodent pests
  4. Trichogramma chilonis against the eggs of lepidopteran borers Correct answer.

Explanation

Trichogramma chilonis is an egg parasitoid widely released against the eggs of moth borers such as sugarcane borers and cotton bollworms. Bacillus thuringiensis and the nuclear polyhedrosis viruses act on lepidopteran larvae, not on aphids or adult whiteflies. Beauveria bassiana is an entomopathogenic fungus used against insects, not rodents.

Question 45Entomology: Insect Pests of Field and Horticultural Crops

Pheromone traps in a cotton field catch a sudden sharp rise in pink bollworm moths. What is the most appropriate interpretation for management?

  1. Egg laying and larval entry into bolls are imminent, so scouting and timely control are needed Correct answer.
  2. A spray is needed immediately on the standing crop
  3. Moths are migrating and will not lay eggs on cotton
  4. The crop is free of the pest and no action is needed

Explanation

Pheromone trap catches record adult activity, and a sharp rise indicates that mating and egg laying will follow within days. The grower should step up scouting for eggs and newly bored bolls and time control to the vulnerable early larval stage. Trap catch alone does not prove the crop is free of the pest.

Question 46Entomology: Insect Pests of Field and Horticultural Crops

The leafhopper Amrasca biguttula on okra causes which characteristic leaf symptom?

  1. White papery blotches between the veins
  2. Downward curling and reddening of leaf margins with stunted growth Correct answer.
  3. Powdery white growth on the upper surface
  4. Large irregular holes eaten out of the lamina

Explanation

Nymphs and adults of the okra leafhopper suck sap from the underside of leaves, causing the margins to curl downward and turn reddish or brown, with stunted plants. Heavy infestation reduces flowering and fruiting. Holes, blotches and powdery growth indicate chewing insects, miners and fungi respectively.

Question 47Entomology: Insect Pests of Field and Horticultural Crops

Which feature distinguishes the damage of the rice leaf folder (Cnaphalocrocis medinalis) from that of the rice stem borer?

  1. The leaf folder folds leaves and scrapes the green tissue, whereas the stem borer hollows the stem Correct answer.
  2. The leaf folder tunnels in the stem, whereas the stem borer feeds on leaves
  3. The leaf folder cuts the panicle neck, whereas the stem borer folds leaves
  4. Both pests produce identical white earheads

Explanation

Leaf folder larvae stitch leaf margins together with silk and scrape the green mesophyll inside the fold, leaving white streaks. Stem borer larvae bore into the stem and kill the central shoot or panicle, giving dead heart and white ear. The two damage types are therefore clearly different.

Question 48Entomology: Insect Pests of Field and Horticultural Crops

Thrips damage on onion leaves typically appears as:

  1. Silvery streaks and curled leaf tips with tiny black specks Correct answer.
  2. Circular purple spots with concentric rings
  3. Soft rot of the bulb with a foul smell
  4. Sunken brown lesions at the bulb neck

Explanation

Onion thrips have rasping-sucking mouthparts and lacerate the leaf surface, removing cell contents so that silvery streaks and patches form. The leaves curl and the tips may dry, and black faecal specks are visible. Soft rot and ringed spots are disease symptoms.

Question 49Entomology: Insect Pests of Field and Horticultural Crops

A grower wants to reduce whitefly-transmitted virus incidence in a tomato nursery. Which integrated measure acts earliest against the vector?

  1. Applying a soil nematicide at transplanting
  2. Spraying a fungicide on the seedlings
  3. Delaying harvesting of the ripe fruits
  4. Using yellow sticky traps and insect-proof netting in the nursery Correct answer.

Explanation

Whiteflies transmit viruses such as tomato leaf curl while probing the plant, so excluding or trapping the vector in the nursery before infection is the earliest effective measure. Insect-proof netting and yellow sticky traps reduce vector entry and population build-up. Nematicides, fungicides and harvest timing do not target the vector.

Question 50Entomology: Insect Pests of Field and Horticultural Crops

The term 'economic threshold level' in crop protection refers to:

  1. The pest density at which control measures should be applied to prevent economic loss Correct answer.
  2. The maximum residue limit permitted in harvested produce
  3. The number of pest generations completed in a season
  4. The dose of insecticide that kills half the test population

Explanation

The economic threshold level is the pest population density at which control should be initiated to stop the population from reaching the economic injury level. It guides timely spraying and avoids unnecessary treatments. Residue limits, lethal doses and generation counts are different concepts.