Chen Wei, Yuan Wenjing, He Renkun, Pu Xinhua, Hu Qiongbo, Weng Qunfang
National Key Laboratory of Green Pesticide, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China.
Insects. 2023 Jun 19;14(6):567. doi: 10.3390/insects14060567.
(1) Background: The cabbage flea beetle (CFB; ) seriously damages the production of Chinese flowering cabbage (CFC; L. ssp. var. ), which is a key leafy vegetable in South China. A large number of chemical insecticides have been sprayed to control this pest; as a result, residues and resistances are becoming an issue. It is necessary to develop biocontrol technologies to address this issue. (2) Methods: Fungal strains were selected based on bioactivity against CFB, and CFC seed pelletization with fungal conidia was subject to evaluation of control efficacy against CFB. The effective mixture of fungus and chemical insecticide was determined based on safety and joint toxicology tests. (3) Results: The screening of 103 strains from 14 genera identified the strain MaGX19S02 (Ma) as the one with the highest virulence. The LCs of Ma to CFB adult and second instar larvae on day 9 post-treatment were 3.04 × 10 and 27.2 × 10 spores/mL, respectively. In the pot test, the pelletization of CFC seeds with Ma conidia (50/25/12.5 mg in 1 g seed with 4 g fillers) demonstrated significant CFB mortalities (45-82%) 20 days after the larvae were introduced. In the field test, the seed pelletization achieved 57-81% control efficacy 14 days after sowing. Furthermore, the combination of Ma with chlorfenapyr (Chl) demonstrated a synergistic effect against CFB; based on this result, we prepared the mixture formulation of 20% Ma-Chl wettable powder (WP). The assessment of the effects of 20% Ma-Chl WP (500× diluent) against CFB revealed 93.33% mortality in the pot test and 61.3% control efficacy in the field test on day 7 post-treatment. (4) Conclusions: The findings demonstrate the potential of Ma to control CFB in the field. Seed pelletization with Ma conidia effectively controlled CFB larvae and protected CFC seedlings, wherein a mixture formulation of 20% Ma-Chl WP had substantial efficacy in controlling CFB adults. Our research provides new methods for CFB biocontrol.
（1）背景：黄曲条跳甲严重危害菜心的生产，菜心是华南地区一种重要的叶菜类蔬菜。为防治这种害虫，已大量喷洒化学杀虫剂；结果，农药残留和抗药性问题日益凸显。因此，有必要开发生物防治技术来解决这一问题。（2）方法：根据对黄曲条跳甲的生物活性筛选真菌菌株，并对用真菌分生孢子进行菜心种子丸粒化处理，评估其对黄曲条跳甲的防治效果。基于安全性和联合毒理学试验确定真菌与化学杀虫剂的有效混合物。（3）结果：从14个属的103株菌株中筛选出毒力最高的菌株MaGX19S02（Ma）。处理后第9天，Ma对黄曲条跳甲成虫和二龄幼虫的致死中浓度分别为3.04×10⁶和27.2×10⁶个孢子/毫升。在盆栽试验中，用Ma分生孢子（1克种子中含50/25/12.5毫克，加4克填充剂）对菜心种子进行丸粒化处理，在接入幼虫20天后，黄曲条跳甲的死亡率显著（45 - 82%）。在田间试验中，播种14天后，种子丸粒化处理的防治效果达57 - 81%。此外，Ma与溴虫腈（Chl）组合对黄曲条跳甲表现出增效作用；基于这一结果，制备了20% Ma - Chl可湿性粉剂（WP）的混合制剂。评估20% Ma - Chl WP（500倍稀释液）对黄曲条跳甲的防治效果，盆栽试验中处理后第7天死亡率为93.33%，田间试验防治效果为61.3%。（4）结论：研究结果表明Ma在田间防治黄曲条跳甲具有潜力。用Ma分生孢子进行种子丸粒化处理可有效控制黄曲条跳甲幼虫并保护菜心幼苗，其中20% Ma - Chl WP混合制剂对黄曲条跳甲成虫具有显著防治效果。我们的研究为黄曲条跳甲的生物防治提供了新方法。
