Tollerup Kristen, Higbee Bradley
Kearney Agricultural Research and Extension Station, Agriculture and Natural Resources, University of California, Parlier, CA 93648, USA.
Trécé Inc., Adair, OK 74330, USA.
Insects. 2020 Nov 9;11(11):772. doi: 10.3390/insects11110772.
Field experiments were conducted in two commercial almond orchards located in the southern San Joaquin Valley during 2016 and 2017 to evaluate a "preventative" strategy to manage spider mites. Pacific mite, McGregor, was identified as the only mite species infesting the experimental sites in both years. We monitored mites weekly in 3.6-hectare plots over approximately 21 weeks in 2016 and in 2017 using guidelines developed by the University of California. In late May, prior to the detection of mites, preventative acaricide treatments, abamectin, cyflumetofen, or etoxazole were applied to the experimental plots at a field rate. In 2016 and 2017, mite densities in all the treatments increased at early-July, peaked at mid-August, and were undetectable by late August. Preventative acaricide-treated plots in 2016 tended to have significantly lower mite densities than in the untreated control plots. Although in 2017, densities in the acaricide-treated plots tended to not significantly differ from control plots. Mite feeding injury, measured as mean cumulative mite-days, did not exceed the economic threshold during the experiment. The biological control agent, sixspotted thrips, (Pergande) likely played a role in controlling mite populations at mid and late August. Our results indicate that a preventative strategy does not play a definitive role in management on almond. Additionally, acaricides with the active ingredient, abamectin, are heavily relied on as preventative treatments. We assessed populations of from the mid and southern San Joaquin Valley and found increased tolerance to a medium level of resistance to the acaricide.
2016年和2017年，在圣华金河谷南部的两个商业杏仁果园进行了田间试验，以评估一种防治叶螨的“预防性”策略。太平洋叶螨（McGregor）被确定为这两年侵扰试验地点的唯一叶螨种类。我们在2016年和2017年，按照加利福尼亚大学制定的指南，在约21周的时间里，每周对3.6公顷的地块进行叶螨监测。5月下旬，在检测到叶螨之前，以田间用量向试验地块施用预防性杀螨剂阿维菌素、氟螨嗪或乙螨唑。2016年和2017年，所有处理中的叶螨密度在7月初增加，8月中旬达到峰值，8月底则检测不到。2016年经预防性杀螨剂处理的地块，其叶螨密度往往显著低于未处理的对照地块。尽管在2017年，经杀螨剂处理地块的叶螨密度与对照地块相比，往往没有显著差异。以平均累计螨日衡量的叶螨取食伤害在试验期间未超过经济阈值。生物防治剂六点蓟马（Pergande）可能在8月中旬和下旬对控制叶螨种群起到了作用。我们的结果表明，预防性策略在杏仁管理中并未起到决定性作用。此外，含有活性成分阿维菌素的杀螨剂被大量用作预防性处理。我们评估了圣华金河谷中部和南部的叶螨种群，发现其对杀螨剂的中等抗性水平的耐受性有所提高。
