Ramos Yordanys, Pineda-Guillermo Samuel, Tamez-Guerra Patricia, Orozco-Flores Alonso Alberto, Figueroa de la Rosa José Isaac, Ramos-Ortiz Selene, Chavarrieta-Yáñez Juan Manuel, Martínez-Castillo Ana Mabel
Instituto de Investigaciones Agropecuarias y Forestales, Universidad Michoacana de San Nicolás de Hidalgo, Km. 9.5 Carretera Morelia-Zinapécuaro, Tarímbaro 58880, Michoacán, Mexico.
Facultad de Ciencias Biológicas, Universidad Autónoma de Nuevo León, Av. Pedro de Alba s/n, Ciudad Universitaria, San Nicolás de Los Garza 66455, Nuevo León, Mexico.
J Fungi (Basel). 2024 Jun 8;10(6):416. doi: 10.3390/jof10060416.
Entomopathogenic fungi have been considered potential biological control agents against the fall armyworm (J. E. Smith), the world's most important pest of maize. In this study, we evaluated the natural infection, molecular characteristics, and biological activity of (Farlow) isolated from larvae of this insect, collected from maize crops in five Mexican locations. Natural infection ranged from 23% to 90% across all locations analyzed. Twenty-four isolates were evaluated on second instars at a concentration of 1.0 × 10 conidia/mL, causing 70% to 98.7% mortality and 60.5% to 98.7% sporulation. Isolates T9-21, Z30-21, PP48-21, and L8-22 were selected to determine their phylogenetic relationships by gene analysis and to compare median lethal concentration (CL), median lethal time (LT), and larval survival. These isolates were grouped into three clades. The T9-21, PP48-21, and J10-22 isolates were closely related (clade A), but phylogenetically distant from Z30-21 (clade B) and L8-22 (clade C) isolates. These genetic differences were not always reflected in their pathogenicity characteristics since no differences were observed among the LC values. Furthermore, isolates T9-21, J10-22, and L8-22 were the fastest to kill larvae, causing lower survival rates. We conclude that native isolates represent an important alternative for the biocontrol of .
昆虫病原真菌被认为是对抗草地贪夜蛾（J. E. 史密斯）的潜在生物防治剂，草地贪夜蛾是世界上最重要的玉米害虫。在本研究中，我们评估了从墨西哥五个地点的玉米作物中采集的这种昆虫幼虫分离出的（法洛）的自然感染情况、分子特征和生物活性。在所有分析的地点，自然感染率在23%至90%之间。以1.0×10分生孢子/毫升的浓度对24个分离株在二龄幼虫上进行评估，导致70%至98.7%的死亡率和60.5%至98.7%的产孢率。选择分离株T9-21、Z30-21、PP48-21和L8-22通过基因分析确定它们的系统发育关系，并比较半数致死浓度（CL）、半数致死时间（LT）和幼虫存活率。这些分离株被分为三个进化枝。分离株T9-21、PP48-21和J10-22密切相关（进化枝A），但在系统发育上与Z30-21（进化枝B）和L8-22（进化枝C）分离株距离较远。这些遗传差异并不总是反映在它们的致病性特征上，因为在LC值之间未观察到差异。此外，分离株T9-21、J10-22和L8-22杀死草地贪夜蛾幼虫最快，导致较低的存活率。我们得出结论，本地分离株是草地贪夜蛾生物防治的重要替代方案。
