Sato Mário Eidi, Da Silva Marcos Zatti, De Souza Filho Miguel Francisco, Matioli André Luís, Raga Adalton
Biological Institute, APTA, Caixa Postal 70, Campinas, CEP 13001-970, SP, Brazil.
Exp Appl Acarol. 2007;42(2):107-20. doi: 10.1007/s10493-007-9081-2. Epub 2007 Jun 5.
The purpose of this study was to evaluate the performance of Neoseiulus californicus (McGregor) for the control of Tetranychus urticae Koch in commercial strawberry fields, under greenhouse conditions, in association or not with the use of acaricides. The N. californicus strain used in this study was tolerant or resistant to several pesticides. Three experiments were carried out in the State of São Paulo, Brazil. For the first experiment, the initial infestation of T. urticae was 87.1 active stages per leaflet. Two applications of propargite were made on the first and the 14th day of the experiment. Approximately 2 h after each propargite application, N. californicus was released at a rate of 3.0 and 1.9 adult mites per plant, respectively, for each application. The population of T. urticae decreased from 87.1 to 2.8 mites per leaflet in the first three weeks. After this period, the population of T. urticae was maintained at low levels (<or=1.5 mites/leaflet) until the end of the experiment (10th week). Propargite and dimethoate sprayed on the strawberry field did not affect significantly the population of this predaceous mite. For the second experiment, the infestation of T. urticae was 29.1 mites per leaflet, when the acaricide chorfenapyr was applied on the strawberry field. The release of N. californicus (2 mites per plant) was made 2 weeks after spraying the acaricide. The population of T. urticae was maintained at low levels (<or=2.8 mites/leaflet) for 8 weeks (evaluation period). The T. urticae infestations in plots with N. californicus were significantly lower than in non-release plots, for the experiments 1 and 2. In the third experiment, the initial infestation of T. urticae was 40.5 mites per leaflet (55.5 active stages/leaflet on release plants; 25.5 active stages/leaflet on non-release plants). Three releases of N. californicus (average rate of 3.0 adult mites/plant), without any acaricide application, were not sufficient to reduce significantly the T. urticae population in release plots (release plants + non-release plants) in 6 weeks from the first release, however, the spider mite population decreased from 55.5 to 7.8 active stages per leaflet on release plants, during this period. Interplant dispersal of N. californicus was low in this strawberry field with high infestation of T. urticae. The studies indicate the viability of the use of this strain of N. californicus for the control of T. urticae in strawberry fields under greenhouse conditions, especially in association with selective acaricides.
本研究的目的是评估加州新小绥螨（Neoseiulus californicus，McGregor）在温室条件下，于商业草莓田中，无论是否与杀螨剂联合使用，对二斑叶螨（Tetranychus urticae Koch）的防治效果。本研究中使用的加州新小绥螨菌株对几种农药具有耐受性或抗性。在巴西圣保罗州进行了三项试验。在第一个试验中，二斑叶螨的初始虫口密度为每小叶87.1个活动虫态。在试验的第1天和第14天分别施用了两次克螨特。每次施用克螨特后约2小时，分别以每株3.0只和1.9只成年螨的释放量释放加州新小绥螨。在前三周内，二斑叶螨的虫口密度从每小叶87.1只降至2.8只。在此之后，二斑叶螨的虫口密度一直维持在较低水平（≤1.5只/小叶）直至试验结束（第10周）。在草莓田上喷洒的克螨特和乐果对这种捕食螨的虫口数量没有显著影响。在第二个试验中，当在草莓田上施用杀螨剂溴虫腈时，二斑叶螨的虫口密度为每小叶29.1只螨。在喷洒杀螨剂两周后释放加州新小绥螨（每株2只螨）。二斑叶螨的虫口密度在8周（评估期）内维持在较低水平（≤2.8只/小叶）。在试验1和试验2中，有加州新小绥螨的地块中二斑叶螨的虫口密度显著低于未释放地块。在第三个试验中，二斑叶螨的初始虫口密度为每小叶40.5只螨（释放植株上为55.5个活动虫态/小叶；未释放植株上为25.5个活动虫态/小叶）。在未施用任何杀螨剂的情况下，三次释放加州新小绥螨（平均释放量为每株3.0只成年螨），在首次释放后的6周内，不足以显著降低释放地块（释放植株 + 未释放植株）中二斑叶螨的虫口数量，然而，在此期间，释放植株上的叶螨虫口密度从每小叶55.5个活动虫态降至7.8个。在这片二斑叶螨虫口密度较高的草莓田中，加州新小绥螨在植株间的扩散率较低。这些研究表明，在温室条件下，尤其是与选择性杀螨剂联合使用时，使用这种加州新小绥螨菌株防治草莓田中的二斑叶螨是可行的。
