A NEW INTEGRATED STRATEGY FOR CONTROLLING THE DESERT LOCUST SCHISTOCERCA GREGARIA (FORSKAL)

Abstract

Nowadays, there is an upsurge in the locust and grasshopper populations in many parts of the world. Any way despite of the increase use of agrochemicals, that reduced the attack by insects. These chemicals are still represents a high risk to field workers and consumers. Accordingly, the use of biological control in these days as a particle solution is too desirable as the only alternative solution to the problem of chemical pesticides usage for long time. Our study revealed that the mortality percentage of the first nymphal instar of the desert locust was 100% after 7, 10 And 19 days when treated with mixture of conc. 5 x 1010 added to 100ppm μl of 10% consult (inhibitor compound), and Metarhizium anisopliae fungal spores at concentrations 5 ×1010, 5 ×109 Spores/ml., respectively. On the other hand, mortality percentage reached 98 and 80% after 6 days by treatment with 100ppm and 0.1ppm of the inhibitor compound respectively. Also, the mortality percentage of the second nymphal instar attained 100% after 20 days by treatment with Conc. 5 x 109 Spores/ml. of fungal spores. Amazingly, the mortality percentage was 100% after 17 days for the third nymphal instar, this by mixing the fungal spores at higher Conc. 5 x 1010 Spores/ml. With the insecticide at Conc. of 100ppm interestingly, the third and fourth nymphal instar, were less sensitive toward lower concentration of insecticide than that of fungal spores usage. Any way, the biochemical pattern revealed that the carbohydrate concentration in haemolymph of infected adult locust was higher than that in the adult non infected control. On the other hand lipid contents and total cholesterol, of the growth inhibitor treated adult insect was sharply increased after 3 days of treatment. Moreover, results showed that, the treatment with fungal spores reduced both the lipid and total cholesterol contents in the insect nymph, while total protein in the nymph of adult locust insect was increased with treatment by both fungal spores and growth inhibitor as a mixture. Also results revealed that the mortality percentage was 100% in both cases of adult and immature insect after 35 days and, 72% after 24 days. Moreover the treatment with mixture of both fungal spores and growth inhibitor reduced the hatchability percentage up to 47.2% in case of treated immature insects compared with 95.5 to the control. However, results also showed that the percentage was 16.9% in case of adult when compared with control. Also sterility percentage was 93.12% in case of immature insect to control, and 97.82% for mature ones compared with the control.