New approaches for controlling the black cutworm agrotis ipsilon (hufn.) (lepidoptera: noctuidae) [electronic resource].

Includes references.

Three commercial products namely MVP11 (delta endotoxin of Bacillus thuringiensis), Match, an I.G.R. (Lufenuron) and Marshal (chemical insecticide) were tested against 2nd and 4th instar larvae of Agrotis ipsilon. Larvae of 2nd instar were allowed to feed on caster-bean leaves dipped for one minute at each concentration used of the three tested materials. Larvae of 4th instar were allowed to feed on a toxicant bait. The LC50 values n h. post treatment with MVP11 were 355.8 and 480.2 p.p.m. for 2nd and 4th instar larvae while those of Match treatment were 98.7 and 120.1 p.p.m., respectively. In the case of the chemical insecticide Marshal, the LC50 values which were estimated 24 h. post treatment were 99.7 and 111.6 p.p.m., respectively. Delayed effect of the three tested materials were also studied among the surviving treated larvae. Occurrence of malformations for different stages could be detected within different concentrations of MVP11 and Match treatments while it didn't occur at all concentrations of chemical insecticide (Marshal). This indicated that, the effect of exposure to different concentrations of MVP11 and Match was extended from treated larvae to the resultant pupae and adults. Larvae which could tolerate exposure to MVP11 or Match concentrations and proceeded their development till successful pupation may fail to emerge as adults. Although, the lower concentrations of Match were less effective than those of MVP11, the latent inhibitory action on different stages exclusion gave an evidence of higher potential for Match than that for MVP11. At concentrations of 100,200,400,800 and 1600 p.p.m. ofMVP11 treatment, the % final effect on different stages were 55.56, 68.89, 76.67, 83.34 and 93.33 % for 2nd instar and 48.88, 61.12, n.22, 79.99 and 90.00 % for 4th instar larvae. The corresponding values of 2nd and 4th instar larvae treated with Match were 57.77, 69.99,77.77,86.66 and 96.67 % and 51.1, 63.32, 71.11, 79.99 and 92.22 % at concentrations of 50, 100, 150, 200 and 250 p.p.m., respectively. Regarding to final percent mortality of different stages, Marshal insecticide treatment was the most effective, resulting in 60.00, 73.33, 86.67, 100 and 100 % for the 2nd instar and 56.67, 70.00, 83.33, 96.67 and 100 % for the 4th instar at concentrations of 50, 100, 150,200 and 250 p.p.m., respectively.

Summary in Arabic.

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