A note on evaluation of some insecticides for the control of potato tuber moth, Phthorimaea operculella, (Lepidoptera: Gelechiidae), on tomato

Potato tuber moth (PTM), Phthorimaea operculella has recently became the most important pest of tomato. No chemical control measurement is yet available. This study was conducted for two seasons (2006/07 and 2007/08) at the Gezira Research Station (GRS), Wad Medani Sudan, to evaluate the efficacy of some insecticides for the control of the pest on tomato. The results showed that Vertimec 018 (abamectin) EC at the dose of 0.225 l/f (4.1 g.a.i./f), Match 050 EC (lufenuron) at 0.30 l/f (15 g.a.i./f) and Icaros 1.8% (abamectin) EC at 0.113 l/f (2.0 g.a.i./f) were found effective in controlling potato tuber moth on tomato, Phthorimaea operculella (Lepidoptera: Gelechiidae). Tomato is the most important vegetable crop grown in Sudan. It occupies the second largest area among vegetable crops cultivation and the farmer can gain the highest income out of its produce per area. In the field it is attacked by a number of insect pests among which are; leaf miners, Liriomyza spp., whiteflies, Bemisia tabaci, African bollworm, Helicoverba armigera and recently potato tuber moth (PTM), Phthorimaea operculella. Among those insect pests potato tuber moth is gaining considerable economic importance. It is an introduced insect (Pollard, 1955) on potato and later it got adapted to tomato. It attacks the fruits after the physiological maturity rendering it unsuitable for marketing. Infestation of the pest is increasing at a very high rate and it became a real threat to the tomato growers (Musa, 2000; Ali, 2003). Damage of more than 50% was found in Sudan (Personal contact). It has a very complicated biology, where the larvae get inside the fruit immediately after emergence. Since 1999 no insecticide was found effective for controlling the pest. The objective of this study was to evaluate some bioinsecticides for the control of potato tuber moth on tomato and consequently reduce toxic hazards in the environment. The experiments were conducted during seasons 2006/07 and 2007/08 at the GRS Farm. The treatments, in both seasons, were identical. In both seasons, tomato variety, Peto 86, was planted by direct seeding on 18/11/2006 and 21/11/2007, respectively. Plants were thinned to two plants per hole two weeks after emergence. The plot size was 3.6 x 7 m. Spacing between mastabas was 140 cm and 50 cm between holes. Fertilization, weeding and irrigation were done as recommended by Agricultural Research Corporation for tomato production. Fungicides (Triadimefon and Bupirimate) were sprayed for the control of fungal diseases. The experiments were laid out in a randomized complete block design with four replications in the first season and three replications in the second season