G. it. Ent., 3 (17): 429-434
December 31, 1987
Economic Injury Level and sequential sampling plan for
Heliothis armigera (Hübner) infesting tomato
by
G. C. TEWARI & G. S. PRASADA RAO
Abstract - Based on damage severity and yield loss relationship, the Economic Injury Level (EIL) for the tomato fruit borer, Heliothis armigera (Hübner) was fixed at 3.48 per cent infestation in peninsular India. The infestation of fruits increased up to the third picking and then showed a declining trend, following in the field a contagion pattern and fitting a Negative Binomial distribution; the Lloyd's index of patchiness and mean crowding with values higher than unity showed its aggregative nature. The treatment decision equations under sequential sampling plan were derived as d0 = 0.9389n - 4.2612 and d1 = 0.9389n + 4.2612, using which a sequential sampling chart has been prepared for field use.
