Biocontrol of Two-Spotted Spidermite

Final Report for FNE95-090

Project Type: Farmer
Funds awarded in 1995: $500.00
Projected End Date: 12/31/1995
Matching Non-Federal Funds: $750.00
Region: Northeast
State: New York
Project Leader:
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Project Information


Note to readers, attached is the complete final report for FNE95-090.

Although we did see some predation of TSSM with P. persimilis, performance might have been improved in several ways. The extremely warm conditions of the 1995 summer created a long unfavorable period for P. perimilis. In most years this is expected to be shorter or less severe. This project might be repeated at other times of the year when conditions are less extreme. Where TSSM outbreaks occur during warm, dry periods selective pesticides might be needed unless effective adapted predators are found. Misting benches or wetting walkways to maintain higher levels would help increase humidity levels and perhaps also reduce temperatures. Monitoring random plants seemed to work well, but was time consuming (>3 hours per visit) and might be refined by noting only mites per plant or number of infested leaves, both of which seem to similarly measure severity. Other susceptible plants should be monitored and either included in the bio-control program or receive preventive treatments compatible with beneficials. Pots were drenched with metalaxyl several weeks to months prior to releasing P. persimilis; it is not clear what, if any, effect this may have had (foliar sprays are considered moderately toxic to nymphs and adults).


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  • Daniel Gilrein


Participation Summary
Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.