Impacts of Different Insecticides on Tuta Absoluta (Meyrick) Larvae with Their Effects on Physiological Characteristics and Fruits Yield of Stressed Tomato Plants تأثیر بعض المبیدات الحشریة على یرقات حشرة التوتا أبسلیوتا وعلى الخصائص الفسیولوجیة ومحصول الثمار فی نباتات الطماطم المجهدة

Abstract

Recently tomato leaf miner, Tuta absoluta, has become one of the major pests and causes genuine damages to tomato production. Consequently, the present investigation was carried out during 2016/2017 and 2017/2018 winter seasons to determine the efficacy of different insecticides (Chlorantraniliprole, Fipronil and Indoxacarb) and their mixture against T. absoluta larvae and study physiological characters and fruits yield of stressed tomato plants. The results showed that, the Chlorantraniliprole insecticide alone and their mixture (Chlorantraniliprole + Fipronil and Chlorantraniliprole + Indoxacarb) were highly effective in relation to tomato leafminer larva reduction than other treatments and untreated control. Chlorantraniliprole + Fipronil treatment proved to be the superior achieving mean reduction level of 79.2% and 76.5% in during the two seasons respectively. The maximum average reduction percentages for the above-mentioned insecticides treatments against leaf miner were 90.1%, 93.4% and 91.1%, respectively in the first season and were 83.5%, 89.8% and 87 % respectively in the second season after seven days of spray. Indoxacarb was less effective on larvae population (49.5% and 49.9%) in both seasons. Chlorophyll a and b, vitamin C, lycopene and relative water content were increased with application of Chlorantraniliprole alone and their mixture. In conclusion Chlorantraniliprole alone and/or in combination with Fipronil or Indoxacarb may recommend for achieving effective control against T. absoluta and use in IPM programs in the tomato fields.