Plant Protection (Entomology and Plant Pathology)
This domain covers identification of pests and diseases, the integrated pest management sequence, and the safe and legal use of pesticides.
IPM and thresholds
Resistant varieties and clean seed come first, then cultural measures such as rotation, stubble removal and timely sowing, then mechanical and biological tools (Trichoderma viride, Trichogramma, NPV, Bt), with chemicals last, applied at the economic threshold level. Indicative thresholds: rice stem borer 5% dead hearts; maize fall armyworm 5-10% plants damaged.
Pests and diseases of major state crops
- Soybean: girdle beetle, semilooper, yellow mosaic, a whitefly-transmitted virus.
- Cotton: pink bollworm and whitefly.
- Wheat: yellow rust, brown rust, loose smut, karnal bunt.
- Gram: Fusarium wilt and pod borer (Helicoverpa).
Pesticide groups
Organophosphates such as chlorpyriphos, carbamates such as carbaryl, pyrethroids such as cypermethrin, neonicotinoids such as imidacloprid; mancozeb is a contact dithiocarbamate fungicide and carbendazim a systemic benzimidazole. CIB&RC registers products under the Insecticides Act, 1968, and label dose, waiting period and crop must be respected.
Worked example
A spray volume of 200 L per hectare at 1.5 ml per litre needs 200 x 1.5 = 300 ml of formulation. If instead the label states 60 g active ingredient per hectare of a 20% formulation, the quantity is 60 / 0.20 = 300 g. The same figure arrives by both routes, which is a useful cross-check.
Traps
- Treating yellow mosaic as a fungal disease; it is viral and is managed through the vector and resistant varieties.
- Expecting a contact fungicide to control a systemic disease.
- Spraying after the threshold is crossed, when damage and loss have already occurred.