Plant Protection (Pests, Diseases, Weeds)
Plant Protection covers identification of pests, diseases and weeds, integrated management, pesticide calculation and safe use.
Recognition and management
Chewing pests (caterpillars, beetles, grasshoppers) damage foliage and fruit; sucking pests (aphids, hoppers, thrips, mites, whiteflies) remove sap and transmit viruses. Learn the named cases: mango hopper, banana pseudostem weevil, citrus leaf miner, chilli thrips, tomato fruit borer, okra shoot and fruit borer. Diseases split into fungal (powdery mildew, downy mildew, anthracnose, wilt), bacterial (citrus canker, bacterial wilt of brinjal, soft rot) and viral (tomato leaf curl, banana bunchy top, chilli leaf curl, all vector-spread). Weeds are grasses, sedges and broadleaf; sedges such as Cyperus are not controlled by grass herbicides.
IPM order: cultural (clean planting material, rotation, resistant varieties, sanitation), mechanical (traps, hand removal), biological (Trichoderma, Bacillus thuringiensis, neem, predators), then chemical as last resort at the economic threshold level, rotating modes of action. Follow label dose and pre-harvest interval.
Worked example. Prepare 200 L of 1% Bordeaux mixture. One percent means 1 kg copper sulphate plus 1 kg lime in 100 L water; for 200 L use 2 kg of each, dissolved separately in wooden or plastic vessels, then poured together into 200 L water. Reasoning: scale every ingredient by the same factor; never use metal containers.
Traps that cost marks
- Spraying insecticides during peak flowering and killing pollinators.
- Confusing canker (bacterial) with anthracnose (fungal).
- Using a grass herbicide against a sedge.
- Ignoring the pre-harvest interval before picking.