Purpose To explore the predatory mite release way with the best control effect on Frankliniella occidentalis through spraying Neoseiulus barkeri on tobacco plants and/or weeds with different times in the field.
Methods N. barkeri was sprayed one to three times with 15-day intervals, respectively, during tobacco growing season in the field. Three N. barkeri release ways including application N. barkeri on both tobacco and weeds, only on tobacco or weeds were set respectively under each release time. The control effect of N. barkeri on F. occidentalis on tobacco field was evaluated by comparing the population of F. occidentalis under different releasing times and methods.
Results The application of N. barkeri on tobacco and weeds for three times had the best control effect on the population of F. occidentalis, and the maintenance time was the longest, with the highest relative control effect of 58.02%. The control effect of twice application of the N. barkeri was the second, and the highest relative control effect was 55.57%. While the control effect on F. occidentalis was the worst after only one application of N. barkeri, and the highest relative control effect was only 49.96% and the duration of the control effect was the shortest. At the same application time, the control effect of N. barkeri applied only to tobacco plant was slightly higher than that only to the weeds, but there was no significant difference between them.
Conclusion The simultaneous release of N. barkeri on tobacco and weeds in tobacco fields can better control F. occidentalis, and the release of N. barkeri on tobacco and weeds at least twice during the tobacco field period (the interval is about 15 days) can achieve relatively good control effect. When the cost is allowed, the more the number of releases of N. barkeri, the better the prevention and control effect on thrips such as F. occidentalis.
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