Population dynamics and development of suitable pest management module against major insect pests of tomato (Solanum lycopersicum L.)

Abstract: Investigation on the population dynamics and evaluation of pest management modules against major insect pests of tomato were carried out at Navsari Agricultural University, Navsari, south Gujarat in rabi, 2007-08. Results revealed that aphid and whitefly population commenced from transplanting with 1.35 aphids leaf^-1 and 0.37 whiteflies leaf^-1, reached to peak level (7.31 aphids leaf^-1and 6.01 whiteflies leaf^-1) at 11 WAT. Peak level of percent infested leaves by leaf miner was 31.75 % at 10^th WAT. The higher population of Helicoverpa on foliage (2.80-3.40 plant¹) was noticed during third week of January to end of February (10-16 WAT). The population of mirid bug, which acts as a potential predator of sucking pests reached peak (1.90-2.05 plant^-1) when population of aphid and whitefly reached maximum. Correlation studies between insect pest population/damage and weather parameters showed that there was significant negative correlation of aphid (r=-0.491) and whitefly (r=-0.449) with maximum temperature and negative significant correlation with minimum temperature (r=-0.645, r=-0.599). Further, the wind velocity showed significantly positive correlation with aphid (r=0.574) and whitefly (r=0.534) population. The wind velocity gave positive and significant correlation with the population of mirid bug as natural enemies. The IPM module was found most promising in reducing the population of aphids (2.1 leaf^-1), whitefly (2.4 leaf^-1), Helicoverpa larva (1.0 plant¹) on foliage. Besides, it reduced leaf infestation by leaf miner (17.8 %) and fruit infestation by Helicoverpa (15.4 %) and increased yield (36445 kg ha¹). The sole insecticidal module was equally effective as IPM module in recording low population of aphids (2.2 leaf^-1), whitefly (2.5 leaf^-1), Helicoverpa (1.1 plant¹), leaf infestation (18.3 %), fruits infestation (16.3 %) and also increased fruit yield (34684 kg ha^-1). The biological module and botanical module ranked third and fourth in efficacy with respect to pest control. Besides pest management, population of mirid bugs (0.8 plant^-1) as natural enemy was also conserved in IPM module. The net ICBR obtained in IPM module was 1:9.45 which was comparable to the insecticidal module (1:15.92).