Spotted bollworm larvae mainly attack bolls, but also feed on squares, shoots and flowers if bolls are not present. If infested during the vegetative state, the caterpillars feed through the terminal buds of the shoots and move downward.
The leaves affected by cotton leafhopper and jassids turn yellowish, then brownish starting from the margins and migrating to the midrib. Leaves gradually show signs of curling before drying completely and shedding.
Black Citrus Aphid affect all citrus trees in all growth stages. The aphids have long piercing mouthparts which they use to suck the sap on shoot tips and young leaves, which leads to distortions of twigs and inflorescences and the curling, rolling or folding of leaves.
American bollworm has been identified to attack more than 180 host plants. These host plants include beans, maize, tomato, legumes etc. It has caused so much damage to the fields and has developed resistance to so many insectides that it has been popularly given the name of a global pest.
Aphids basically belong to Aphidoidea Family. They are small sap-sucking insects like greenfly and blackfly. However, they are not harmful to crops in early stage or in small or moderate numbers. Aphid’s infest severe damage to leaves and shoots and also causes damage to plant growth.
The symptoms of Alternaria blight usually occur in summer and are depicted by the presence of angular or circular spots of around 4 to 7 mm in diameter. In some bad cases, the spot become 3 cm in diameter.
Angular Leaf Spots are very easy to distinguish since the plants suffering from this develop leaf spots that follow leaf veins. It is caused by bacteria such as Pseudomonas syringae (cucurbits) and Xanthomonas fragariae (strawberries) that survive in seeds and plant debris.
Castor Semilooper achaea janata is widely distributed throughout India. Though castor is the principal host plant for them, it has also been found to be predating on tea, sugarcane, pomegranate, banana, rose, grape fruits, citrus etc.