EVALUATION OF SOME NON-TRADITIONAL PESTICIDES AGAINST THE TWO POD BORERS Helicoverpa armigera AND Etiella zinckenella POPULATION INFESTING COWPEA IN THE NEWLY RECLAIMED REGIONS

The two pod borers Helicoverpa armigera Hubner and Etiella zinckenella Treitschke are the most destructive insect pests which infest several crops of leguminosae in Egypt. Field experiments were conducted to evaluate the efficacy of some relatively safe compounds beside the conventional pesticides for control of these pests on cowpea, Vigna ungiculata under the conditions of newly reclaimed regions.
The results revealed that most of the treatments were able to suppress the levels of infestation to different degrees according to the nature of the tested compounds and the number of sprays applied. Application of non-traditional compounds such as thiamethoxam (neonicotinoid group) or Indoxacarb (oxadiazine group) significantly reduced the larval populations of H. armigera by 76 and 70% and E. zinkenella by 58 and 55%, respectively. Plots sprayed with methoxyfenozide (non-steroid ecdysone agonist )provided satisfactory control (60% reduction) against H. armigera population while exerted weak  activity(< 26%) against E. zinkenella population.
On the other hand, the potency of the common neurotoxic pesticides; chlorpyrifos (organophosphate) or cypermethrin (pyrethroid) were still the most effective pesticides against both species giving 76-81% reduction in infestation.
However, all the tested pesticides and the rates used had low residual effect against the two insects  and thus, weekly applications to protect the plants of new insect attack were necessary. The treatments received six applications, throughout the entire season, effectively contained the damage caused by pest population more than those received four or two applications.
At harvest, high grain yield was obtained in the plots treated 6 times with the tested compounds. In general, Chlorpyrifos was the superior compound being registered (45.9%) increase in yield over the untreated control value, followed by Thiamethoxam (41.6%), Indoxacarb (39.0%), Cypermethrin (38.8%) then Methoxyfenozide (33.9%). Moreover, remarkable elevation in the percentages of damaged grains (~ 28.0%) was recorded in all treatments sprayed twice throughout the season, while the corresponding values in those received  6 applications were restricted within 13.6-16.4%.
The effectiveness and moderate persistence of such new compounds, beside their low mammalian toxicity make them promising agents when used alone or with other control measures on cowpea plantations.