Effect of afternoon and morning applications of Green Muscle® and phenylacetonitrile on Desert Locust nymphs, <i>Schistocerca gregaria</i> (Forskål, 1775)

Abstract

An experiment was carried in Niger to identify the best time to apply Green MuscleR and Phenylacetonitrile to control nymphs of Schistocerca gregaria (Forskal, 1775). Ten treatments (50 g of GM/ha, 25 g of GM/ha, 25 g of GM + 10 ml of PAN per ha, 12,5 g of GM/ha and 12,5 g of GM + 10 ml of PAN per ha, each of them applied at 9:00 am and at 5:00 pm) were tested in a randomized complete block design with 3 replicates. Plots were field enclosures of 20 m2 (5 x 4 m) containing millet plants to feed nymphs. Two hundred and forty nymphs of desert locust in the third instar were released in each enclosure one day before the application. Observations on mortality were done in the enclosures and in cages for a close survey. Sporulation of the fungi was also followed on dead nymphs. Results were analyzed with Genstat software using ANOVA, Student-Newmann-Keuls test and Standard error of mean. In the field enclosures with afternoon application, nymph mortality with 25 g of GM.ha-1 was significantly (P . 0.05) higher than those with 12,5 g of GM.ha-1. Mortalities were significantly (P . 0.05) higher with afternoon application for any dose and in cages left under the tree shade. There was no significant (P . 0.05) difference on mortality in cages for a given moment of the day. The fungus sporulated on dead nymphs from field enclosures and cages. So, afternoon applications of Green Muscle may increase mortality rate of Desert locust nymphs.

Keywords: Biopesticide, pheromone, locust control, Niger.