Influence of Abiotic Factors on Changing Scenario of Tea Mosquito Bug (Helopeltis antonii Sign.) Infestation on Cashew in Chhattisgarh

摘要

The world production of cashew is estimated to be around 20.83 lakh tons. India's share in the world raw nut production accounts to about 25%. The targets for nut production are 16 lakh tons for the year 2015. In India, cashew cultivation area has increased from 706 to 780 thousand ha during 1998-99 to 2003-04 but average productivity remained 800 kg/ha. There are various factors responsible for yield reduction in cashew, in which the insect pest problem is a major one. Among them the tea mosquito bug (TMB - Helopeltis antonii Sign.) is the important limiting factor. Both the nymph and adult of tea mosquito bug suck the sap from the tender shoots, young leaves, inflorescence, developing apple and nuts. Looking to pest problem a survey was conductedon weekly basis in randomly selected trees in an adult cashew plantation of different blocks of District-Jagdalpur as well as S.G. College of Agriculture & Research Station, IGKV, Jagdalpur (C.G.) during 2004-05 to 2010-11 to study the infestation and intensity of tea mosquito bug. To study the influence of climatic factors weather data were collected from the meteorological observatory of S.G. College of Agriculture & Research Station, IGKV, Jagdalpur (C.G.) and correlation was also analyzed. The damage of TMB was seen from November to June in flushing to fruiting stage of the cashew trees. The TMB damage varied from 0.02-12.30 and 0.05-16.46% on shoot and panicle in 2004-05 to 2010-11, respectively. The maximum and minimum temperature had significantpositive influence and relative humidity (morning and evening) had significant negative influence on TMB damage both on shoot and panicle in majority of the observing years. The rainfall had not much influence on infestation of this insect pest.