A considerable number of studies involving laboratory-reared locusts have been devoted to the hormonal regulation of lipid release required as “fuel” for long distance flights. In subsequent studies, similar experiments were performed in Agadez (Republic of Niger) with insects captured in the field. These provided the basis for the application of various products to flying S. gregaria. The aim pursued by these trials was twofold: not only to measure the induced mortality rates, but also to quantify any reduction in the insects` physical condition. The substances sprayed onto flying S. gregaria caused mortality rates of at least 40 % (Melia extracts), 70 - 90 % (neem products), and 100 % (Metarhizium flavivoridae). The same products applied to resting S. gregaria failed to kill them. However, a roughly 35 % reduction in their hyperlipemic response was measured. Further study is required to ascertain whether or not the treated locusts are still capable of sustained flight activity. Complete loss of hyperlipemic response was established in the small numbers of insects that survived flight application.
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