Susceptibility of five pearl millet (Pennisetum glaucum L. Ecotypes to the nymphal instars of the Migratory locust Locusta migratoria migratorioides (Reiche and Farmaire) infestation

Abstract

The laboratory experiments were conducted at the unit of biological control, Insectary laboratory of the Department of Crop Protection, Faculty of Agriculture University of Khartoum, Shambat, during the period from the beginning of May 2014 to the beginning of January 2015. The experiments were carried out under semi-field conditions (cage- experiment). The objectives of the study were to study investigation and evaluation the susceptibility of five ecotypes of (Pearl millet Pennisetum glaucum var.) on the life system of the solitary African Migratory Locust. The main objective was to detect the most preferred food variety on the development of nymphal instar (3rd & 4th in stars) of the African Migratory Locust Locusta migratoria migratorioides (Lin.). Five different experiments with five ecotype varieties of Pearl millet Pennisetum glaucum var were setup. Each experiment with three replications were applied topically on the 3rd and 4th nymphal instars. Each treatment replicated 3 times. Each experiment took duration of four days. Millet plants were gown in ground basin and plastic cup to feed the locusts and for experiment application techniques. Data were recorded daily after 24 hours from beginning of experiments and were followed until the fourth day. The food preference and ecotype susceptibility evaluation was based on Amount of food-intake in gram, Weight of food-ingested and digested in gram, percentages, and Amount of weight of feces in gram. The results showed the significant difference of susceptibility of five varieties ecotype of pearl millet. The susceptibility of feeding by 3rd and 4th nymphal instars was clearly observed in all ecotypes. According to the study results showed the preference of ecotypes by nymphs was increased according to increasing of application time. The high one was Bayouda-late maturing compared to four other ecotypes of treatments. Then Kano-late maturing, Wad elahow-late maturing, Bayouda-early maturing and Dembi-early maturing respectively. During the experiments were noticed that the preference of five ecotypes were high in the first reading and third reading of experiments. However the results revealed that the susceptibility of five ecotypes of pearl millet Pennisetum glaucum var, according to remain amount of feces in any ecotype variety. The least amount of reminder feces was in Bayouda-late maturing ecotype, this means that the biggest part of the food-intaken was ingested, digested and assimilated according to the four others ecotypes. The bigger percentages of ingested amount of food consumption for five ecotypes of pear millet Pennisetum glaucum var, with 3rd and 4th instars of African migratory locust ranked as above mentioned. The research concludes that further works on evaluation of susceptibility of pearl millet varieties with different pest, particularly in migratory locust is recommended, thus the crucial role in order to detect the target palatable variety as a trap in pest management control.