Phospholipase A2 (PLA2) catalyzes the committed step for eicosanoid biosynthesis. Two cellular PLA2 genes (iPLA2 and cPLA2) have been identified in Spodoptera exigua. PLA2 activity varied among developmental stages and different tissues. There was a positive correlation between PLA2 activities and their expression levels. Interestingly, there was significant inhibition by sPLA2 inhibitor, suggesting a presence of sPLA2 in S. exigua. An entomopathogenic bacterium, Xenorhabdus hominickii, infection suppressed expression of PLA2 genes and its extract inhibited enzyme activities. Oxindole of a bacterial metabolite of X. hominikii inhibited PLA2 activity and expression.

Trehalose is a major blood sugar in insects. It functions as carbohydrate nutrient source to all tissues with a relatively constant level and also serves as a cryoprotectant at high levels in some insects. Thus, its hemolymph levels need to be controlled according to physiological conditions. An insulin-like peptide, SeILP1, was identified and showed to mediate down-regulation of the hemolymph trehalose levels of Spodoptera exigua larvae. This study showed that hemolymph trehalose levels of S. exigua significantly increased upon immune-challenge and under starvation in a time-dependent manner. During up-regulation of the hemolymph trehalose, the gene expression of trehalose phosphate synthase significantly increased, but that of trehalase significantly decreased. Injection of biogenic monoamines, such as octopamine and serotonin, did not increase the hemolymph trehalose levels. Either treatment of arachidonic acid or eicosanoid biosynthesis inhibitor did not change the hemolymph trehalose levels. However, injection of adipokinetic hormone (AKH) of Manduca sexta significantly increased the trehalose levels. Interrogation of Spodobase identified an AKH-like gene of S. exigua. Its expression increased with starvation in the larvae. Its RNA interference significantly prevented the up-regulation of the hemolymph trehalose levels in S. exigua.

Beet armyworm, Spodoptera exigua is difficult to control using chemical insecticides because of the development of insecticide resistance. Various control agents may use for eco-friendly beet armyworm managements, Entomopathogenic fungus is one of the promising control agents as an alternative to chemical control agent. At previous study we isolated a number of entomopathogenic fungi from soil samples and selected three entomopathogenic fungi, Metarhizium anisopliae FT83, Paecilomyces fumosoroseus FG340 and Metarhizium anisopliae FG344 which had high virulence against larva of beet armyworm. To select an isolate having high virulence at high temperature against S. exigua, thermophilic pest, we conducted bioassay at five different temperatures(15, 20, 25, 30, 35℃). These three isolates showed the high mortality and low LT50 at 30℃. To select substrate for mass production these isolates were inoculated(5×10⁴/㎖, 20㎖) at barley, unpolished rice, wheat bran and rice bran and incubated for 14 days at 25℃. Wheat bran showed highest conidia production of M. anisopliae FT83 and P. funosoroseus FG340 and barley was suitable for M. anisopliae FG344.

파밤나방 핵다각체병ㅂ이러스의 기주곤충 및 나비목해충에 대한 병원성과 10종 baculovirus의 파밤나방 유충에 대한 교차감염을 조사하여 방제에 이용하고자 시험을 수행하였다. 난에대한 중앙치사농도()는 2.855 다각체/ml로 유충보다 높았다. 령별 은 3령이 1.422 다각체/ml로 1령보다 1.16배, 5령보다 .11배의 높은 병원성을 나타냈다. 각 령의 중앙치사일수()은 1.56 다각체/ml에서 4.26~5.04일이었다. 8종 나비목 해충에 대한 파밤나방 핵다각체병바이러스의 병원성은 기주곤충인 파밤나방에서만 인정되었고 10종의 곤충간상바이러스 중 Autographa californica MNPV, Mamestra brassicae MNPV 및 Trichoplusia ni MNPV 등 3종이 파밤나방 유충에 대해 교차감염을 일으켰다.