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Symptom and damage in crops

1. Methods of detection of Insects APP311

2. Symptoms and types of damage caused by insect pests Any insect that feeds on any part of a plant is termed as a pest. The types and symptoms of damage caused to the plants vary according to the feeding habit and mouthparts of insects. The damages caused by the insects are grouped into direct and indirect damages.

3. Direct damages Injuries caused by biting and chewing insects, piercing and sucking insects, internal feeders, subterranean root feeders and storage pests fall under this category.

4. Borer feeding Leaf skeletonization

5. Hopper Burn Leaf curl by Thrips

6. Damages caused by insects having biting and chewing type of mouth parts: Defoliation ( eg ) Hairy Caterpillars Scrapping and skeleonization ( eg ) Epilachna in brinjal Feeding on terminal buds ( eg ) Brinjal shoot borer Notching the edges of leaves ( eg ) Ash weevil on brinjal Shot holes on leaves ( eg ) Flea beele , Tortoise beetle Windowing ( eg ) Spodoptera in Banana Irregular holes on leaves ( eg ) Grass hopper Leaf rolling, twisting and webbing ( eg ) Mangoleaf twisting weevil

7. Damage caused by insects having piercing and sucking type of mouth parts: Chlorosis ( eg. ) aphids on Groundnut Speckling ( eg. ) Banana tingids Silvering ( eg. ) Onion thrips Mosaic ( eg. ) Bhendi aphids Hopper burn ( eg. ) Bhendi jassid , BPH Crinkling and curling of leaves ( eg. ) chilli thrips Upward and downward curling of leaves ( eg. ) Chilli aphids Downward cupping of leaves ( eg. ) Brinjal aphids Elongation of petioles ( Eg ) Chilli yellow mite

8. Continued.. 10) Distortion and clustering of leaves ( eg. ) Mealy bug on coconut 11) Tissue proliferation ( Eg. ) Mealy bug on Hibicus 12) Shoot drying ( eg. ) Tea mosquito bug on neem 13) Flower and fruit drop/shedding ( eg ) Mango hoppers 14) Scab/corky/ outgrowth ( eg. ) Tea mosquito bug on guava

9. Damage caused by internal feeders Stem, shoot, boll, fruit and capsule boring ( eg. ) Pomegranate fruit borer Leaf mining ( eg. ) Citrus leaf miner Gall formation ( eg. ) Mango leaf gall Frothing and gummosis ( eg ) Spittle bug on jack Oozing out of sap ( eg. ) Coconut red palm weevil

10. Damages caused by subterranean pests Removal of sown seeds ( eg ) Ants on amaranthus Wilting of plants due to feeding on roots ( eg ) Root grub on cauliflower Tunnelling in vines and tubers ( eg ) Potato tuber moth Damage caused by stored product pests Internal feeding of grains ( eg ) Pulse beetle Surface scrapping of grains ( eg ) Corcyra moth

11. Indirect damages Oviposition injury ( eg ) Cicada, Cowbug Making harvest difficult ( eg ) Red antson mango, lablab Aphids Contamination and loss of quality ( eg ) Brinjal fruit borer Making nests or cases out of plant parts ( eg ) Leaf cutter bee Insect carriers ( eg ) Homopterans (Mealy bug) carried by ants Transmission of plant disease by insects Virus – (1) Whitefly ( eg ) Bhendi Vein clearing (2) Thrips ( eg ) Tomato spotted