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Pest Management in Cashew

Management of Tea Mosquito Bug

(a) Cashew tree looks like blighted. What disease is this and how to control it?

(b) What is the reason for and how to control the blight disease in which the twigs of cashew dry?
(c) Some dried leaves are seen amidst green leaves. What is this disease?
(d) Why do the leaves of cashew dry off?
(e) One year old cashew plant flushed twice and dried completely. Why?
(f) Why the cashew flowers get burnt despite spraying of insecticides?
(g) TMB could not be controlled even after spraying twice. Why?
(h) Why do tender nuts blacken and dry?
(i) After flowering, the panicle turns black. What is the reason and how to control this?

The blighted appearance and burnt symptoms with drying of cashew leaves is due to feeding damage by the tea mosquito bug (TMB) Helopeltis antonii, and is not a disease symptom. The adult and young insects (nymphs) suck the plant sap , and the toxic saliva infected by the insect leads to drying of the damaged portion. As the insect feeds on tender shoots, flower panicle as well as immature nuts, these parts get dried up.The repeated flushes are re-attacked and these also get dried up. Any spraying taken up after severe feeding damage will not be of any help and hence drying of flower panicles/twigs occur in spite of spraying.

(a) As per our experience, cashew inflorescence dries in case there is cloudy weather for 2-3 days. Is this due to TMB damage or due to weather itself? How can we prevent the damage or at least limit the damage?

(b) Is there any relation between cloudy weather and TMB population build up?

The inflorescence drying during cloudy weather has been constantly noticed, however, the sudden rise in temperature following cloudiness is suspected to lead to flower drying. The TMB population build up is also more under these conditions.

(a) What are the non-chemical methods of TMB control?

(b) What are the bio-pesticides that can be used for TMB control?

(c) Whether neem oil can be used instead of endosulfan for plant protection in cashew??

It is presently debated whether pesticidal usage can be reduced in TMB management. However, in trials involving different bio-pesticides (derived from neem, pongamia, dill, custard apple and others plant species), the presently recommended pesticides performed better. Use of neem oil in place of a pesticide may not provide immediate pest reduction and repellency is not long lasting.