干旱区生态环境知识资源中心

Melia volkensii extracts were tested for the first time under field conditions in the southern Tamesna Desert (Republic of Niger). S. gregaria larvae caught in the field and larvae hatched from egg pods brought from Germany to Agadez were both treated with these extracts. Although these experiments had pilot character in every respect, a number of important findings were made, some of them unexpected. Application of an oil-based formulation containing 1000 ppm of biologically active compounds (10 liters per hectare) caused retarded growth and a considerable delay in the onset of sexual maturity in the imagoes, i.e. was possible to reduce by 30-40 days the potential reproductive period of adult S. gregaria individuals that had been treated with Melia extract as larvae. Moreover, initial studies indicated a high likelihood that active compounds contained in Melia extracts are capable not only of halting the feared gregarization process that S. gregaria undergoes, but indeed of reversing it.