豇豆花期豆大蓟马种群动态监测及生物药剂田间防效评价

Population Dynamics Monitoring and Field Biological Control of Megalurothrips usitatus during Flowering Stage of Cowpea

豆大蓟马(Megalurothrips usitatus)是海南豇豆(Vigna unguiculata)的主要害虫,其体型微小、隐蔽性强,是当地豇豆种植户过量使用化学农药的最主要防治靶标。为准确筛选安全有效且具有应用前景的生物防治药剂,调查三亚市崖州区豇豆田间豆大蓟马成虫种群发生动态,分别采用含孢子150亿个 · g^(-1)球孢白僵菌可湿性粉剂(WP)、32 000 IU · mg^(-1)苏云金杆菌WP、8 000 IU · μL^(-1)苏云金杆菌悬浮剂(SC)、含孢子150亿个 · mL^(-1)金龟子绿僵菌CQma421可分散油悬浮剂(OD)、含孢子50亿个 · mL^(-1)爪哇虫草菌JS001 OD和0.3%苦参碱水剂(AS)6种生物药剂进行豇豆田间药效试验。结果表明:豇豆花期豆大蓟马成虫种群密度与调查时间相关,18:00时蓟马数最高,为22.40头 · 朵^(-1)。通过比较不同施药时间的防效发现,8:00时施药防效最好的为0.3%苦参碱AS,药后7 d校正防效达到最高,为59.63%;13:00施药时所有药剂都无明显防效;18:00时施药防效最好的为爪哇虫草菌JS001 OD,药后7 d校正防效为62.37%,而此时苦参碱AS仅在药后3 d校正防效达到最高,随后防效逐渐减弱。喷施上述生物药剂后,豇豆“黑头黑尾”率显著降低。综上,合理施用苦参碱AS、爪哇虫草菌JS001 OD和金龟子绿僵菌CQma421 OD能有效提高对豆大蓟马的防效,研究结果可为减少豇豆农药施用提供依据。

Megalurothrips usitatus,a tiny and discreet pest,is a major threat to cowpea(Vigna unguiculata).It is the primary target of excessive chemical pesticide use among local cowpea growers.To accurately select safe,effective,and promising biocontrol agents,we investigated the population dynamics ofM.usitatus in cowpea fields in Yazhou District,Sanya City.15 billion spores · g~(-1) of Beauveria bassiana WP,32 000 IU · mg~(-1 )of Bacillus thuringiensis WP,8 000 IU · μL~(-1) of Bacillus thuringiensis SC,15 billion spores · mg~(-1 )of Metarhizium anisopliae CQma421 OD,5 billion spores · mg~(-1) of Cordyceps javanica JS001 OD and 0.3% of martrine AS were used in field trials of cowpea.Results showed that the population density of M.usitatus during the flowering stage of cowpea was time-dependent,with the highest count at18:00,reaching 22.40 thrips per flower.Comparing the efficacy of different application times,the most effective treatment at 8:00 was 0.3% martrine AS,achieving a corrected efficacy of 59.63% after 7 days.At 13:00,all treatments showed no significant efficacy.At 18:00,C.javanica JS001 OD exhibited the highest efficacy,reaching 62.37% after 7 days,whereas martrine AS peaked on day 3 and subsequently declined.Application of the aforementioned biopesticides significantly reduced the occurrence of ‘black head and tail’ in cowpea.In conclusion,strategic application of martrine AS,C.javanica JS001 OD,and M.anisopliae CQma421 OD enhances control efficacy against M.usitatus.These findings provide a basis for reducing pesticide use in cowpea cultivation.