POPULATION DISPERSION OF HELOPELTIS ANTONII SIGNORET IN CASHEW PLANTATIONS IN COASTAL KARNATAKA
C. MANJA NAIK *
AICRP ON SOYBEAN, ZONAL AGRICULTURAL RESEARCH STATION, UNIVERSITY OF AGRICULTURAL SCIENCES, GKVK, BANGALORE-560 065, INDIA.
A.K. CHNKRAVARTHY *
AICRP ON SOYBEAN, ZONAL AGRICULTURAL RESEARCH STATION, UNIVERSITY OF AGRICULTURAL SCIENCES, GKVK, BANGALORE-560 065, INDIA.
M.I. NAIK *
AICRP ON SOYBEAN, ZONAL AGRICULTURAL RESEARCH STATION, UNIVERSITY OF AGRICULTURAL SCIENCES, GKVK, BANGALORE-560 065, INDIA.
B. DODDABASAPPA *
AICRP ON SOYBEAN, ZONAL AGRICULTURAL RESEARCH STATION, UNIVERSITY OF AGRICULTURAL SCIENCES, GKVK, BANGALORE-560 065, INDIA.
*Author to whom correspondence should be addressed.
Abstract
The population dispersion of Tea Mosquito Bug, Helopeltis antonii Signoret was monitored during noni-flushing, flushing, panicle emergence and nut and fruit developmental stages on cashew (variety V-4) trees 12 years old in coastal Karnataka. The variance to mean ratio > 1 indicated aggregated distribution of TMB adults at higher level density (>1/shoot). At lower levels of density (<1/shoot), variance to mean value close to 1 projected random distribution. Taylors' Power Law based on cashew plant phenology projected significant relationship between (S2) and (X) of the H. antonii population. Slope values greater than 1 (b = 1.82 and 1.76 with R2 = 1.01 and 0.97) indicated aggregated TMB distribution during flushing to nut developmental phase of, the trees in 2006-07 and 2007-08, respectively. The TMB population during post-flowering season (April-August) was low and the gradient values < 1 (b = 0.98 and 0.88) for 2007 and 2008, respectively indicated regular distribution. These variations in TMB distribution on cashew indicated the trends in preference for food sources by the bugs and facilitate development of appropriate management strategy.
Keywords: Population dispersion, cashew plantation, Helopeltis antonii, coastal Karnataka