Tecnológico Nacional de México, Campus Cuauhtémoc, Chihuahua, Mexico.
Centro de Investigación en Alimentación y Desarrollo, A.C., Campus Cuauhtémoc, Chihuahua, Mexico.
Neotrop Entomol. 2024 Aug;53(4):917-928. doi: 10.1007/s13744-024-01172-3. Epub 2024 Jun 28.
Granuloviruses (GVs) Betabaculovirus associated with the fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), especially those of the type I, have scarcely been studied. These GVs might be an effective alternative for the biocontrol of this insect. In this study, the native GVs SfGV-CH13 and SfGV-CH28 were isolated from FAW larvae and characterized for morphology, molecular traits, and insecticidal activity. The elapsed time between symptomatic infection of larvae and stop feeding as well as the weight of larvae before death or prior to pupation were also evaluated. Both GVs had ovoid shape and a length of 0.4 µm. They had the same DNA restriction profiles and their genome sizes were about 126 kb. The symptomatic infection with the tested GVs mainly caused flaccidity of larva body and discoloration of integument. The integument lysis was only observed in 8% of infected larvae. Infected larvae gradually stopped feeding. Overall, these symptoms are characteristic of infections caused by type I GVs, which are known as monoorganotropic or slow-killing GVs. The median lethal dose (LD) values for SfGV-CH13 and SfGV-CH28 isolates were 5.4 × 10 and 1.1 × 10 OBs/larva, respectively. The median lethal time (LT) ranged from 17 to 24 days. LT values decreased as the viral dose was increased. The elapsed time from symptomatic infection until pupation and body weight of larvae (third instar) were higher with SfGV-CH28 than SfGV-CH13. Both granulovirus isolates were able to kill the FAW larvae from the 12th day.
球孢白僵菌（GVs）贝塔杆状病毒与草地贪夜蛾（FAW），Spodoptera frugiperda（J.E. Smith）（鳞翅目：夜蛾科）有关，特别是那些 I 型的，几乎没有被研究过。这些 GVs 可能是这种昆虫生物防治的有效替代品。在这项研究中，从 FAW 幼虫中分离出了本土的 GVs SfGV-CH13 和 SfGV-CH28，并对其形态、分子特征和杀虫活性进行了表征。还评估了幼虫出现症状感染到停止进食之间的时间以及幼虫死亡或化蛹前的体重。两种 GVs 都呈卵形，长 0.4 µm。它们具有相同的 DNA 限制图谱，基因组大小约为 126 kb。经测试的 GVs 感染幼虫后，主要导致幼虫身体松弛和体壁变色。只有 8%的感染幼虫观察到体壁溶解。受感染的幼虫逐渐停止进食。总的来说，这些症状是由 I 型 GVs 引起的感染的特征，这些 GVs 被称为单器官亲和或缓慢致死的 GVs。SfGV-CH13 和 SfGV-CH28 分离株的半数致死剂量（LD）值分别为 5.4×10 和 1.1×10 OBs/幼虫。中位致死时间（LT）范围为 17 至 24 天。LT 值随着病毒剂量的增加而降低。从出现症状感染到化蛹和幼虫（三龄）体重的时间间隔，SfGV-CH28 比 SfGV-CH13 更长。两种球孢白僵菌分离株都能够在第 12 天杀死 FAW 幼虫。
