Image of bell peppers showing broad mite damage. Photo by Steve Bogash
Broad mites have recently been more of a problem on tomatoes and peppers in Pennsylvania and its neighboring state, Maryland. Already this year, Steve Bogash of Penn State is seeing the broad mite problem repeat itself. Based on his experience, Bogash is recommending treatments for broad mites earlier in the season to prevent them from building and reaching economically damaging levels on tomatoes and peppers.
For 2015, Steve is recommending a miticide application specifically for broad mites at the formation of the first flowers and a second application four weeks later. Bogash knows that by the time damage is observed, it is far too late to react. An early application timing is advisable if broad mites have been a problem in past production. Bogash warns that growers who delay treatments risk sustaining high economic losses by the time damage is observed.
Steve detected broad mite feeding damage during an inspection of transplants last month in greenhouse peppers. Therefore, pepper and tomato plants may require miticide applications for broad mites as early as the seedling stage. According to Bogash, unlike spider mite damage, plants attacked by broad mites may not recover and often are permanently stunted.
The challenge in minimizing damage is due to the extreme difficulty in scouting for them. It's not just their very small size but where they feed. Unlike spider mites that can readily be seen without a hand lens and are associated with feeding on the bottom of leaves, broad mites feed within growing meristems and require higher magnification than most growers utilize. Bogash has often observed fruit damaged from broad mites but no discernable broad mites in dissected plant meristems. He is convinced this damage was from broad mites, but they appear to have either moved on or been killed before the damage was spotted. This appears to be a common problem.
Dr. Tom Kuhar, VA Tech vegetable entomologist, has observed similar problems in commercial tomato and pepper production in Virginia. According to Dr. Shelby Fleischer of Penn State, it only takes seven to eight days for mites to go from egg to adult when temperatures are above 85 degrees. Fleisher reported pesticide applications can flare mite problems by eliminating predators and by increasing the reproductive rate of mites at sublethal doses. (Source: Vegetable and Small Fruit Gazette).
Chemical Management: Portal XLO Miticide
Portal XLO has demonstrated outstanding efficacy on broad mite in university research studies. Based on efficacy trials conducted, Portal XLO is very effective at controlling broad mites (Kuhar). Moreover, growers producing quality peppers and tomatoes depend on Portal XLO to protect plants while maintaining profitable yields.
Since it was first introduced in 2009 for fruiting vegetables, Portal XLO has provided growers fast knock down of mite populations, including two-spotted spider mites. Portal XLO is generally applied mid-season or upon the establishment of an economical threshold. Since broad mite damage on fruiting vegetables may occur much earlier in the growing season, growers should consider Portal XLO applications when broad mites are first detected or the damage to plants is believed to be from broad mite feeding.
Portal XLO is classified by IRAC in Group 21A and should be rotated with miticides with a different mode of action. Because Portal XLO is a contact miticide, optimal performance requires uniform and thorough spray coverage. Improving spray coverage with Portal XLO will improve the control of broad mites and two-spotted spider mites. The addition of a nonionic activator type wetting, spreading, or penetrating adjuvant is recommended to improve coverage and to maximize uniformity of spray applications.
Portal XLO works quickly to knock down mites and provides rapid cessation of feeding. It controls all motile stages of mites - larvae, nymphs, and adults. In addition, Portal XLO provides control of whiteflies and tomato psyllid in fruiting vegetables. The recommended use rate is 2 pints per acre, using a minimum of 20 gallons of water per acre. The maximum use per acre per crop cycle is 4 pints, and the preharvest interval is 1-day.
Article by Michael Myers, Technical Sales Representative, Nichino America, Inc. and reviewed by Steve Bogash, Extension educator and researchers from Virginia Tech and University of Maryland
Other Materials for Broad Mite Management
Steve Bogash, Educator / Researcher, Penn State Extension
While Portal XLO has proven to be an excellent miticide for managing broad mites in our high tunnels at the Penn State SE Research Farm (SEAREC and Landisville Farm), there are other options to control this pest. Here are some other options for broad mite control:
Oberon: The rate for Oberon is 7.0 - 8.5 fl oz/acre and allows for up to 3 applications per season. The PHI is one day on tomatoes and peppers. Since Oberon has an IRAC code of 23 and Portal XLO is 21A, this could be a good material to rotate to in order to prevent pesticide resistance.
Zeal: Zeal is registered for use on peppers and eggplant for spider mites in PA, but has a special needs label in Florida for broad mites. With an IRAC code of 10B, Zeal could be important in managing resistance. Since spider mites are a constant irritant in tunnels, by managing spider mites, you also get broad mite control. The rate is 2.0 - 3.0 oz/acre with a 7-day PHI.
Met 52: Growers in California have found Met52 to be an effective biological control for broad mites. The label rate is 8.0 - 64.0 fl oz/acre with a 0-day PHI.
Grandevo: Work in Florida demonstrated efficacy in using this biological for broad mites. The rate is 2.0 - 3.0 lbs/acre with a 0-day PHI
Venerate: This newest product from Marrone Bio Innovations has also demonstrated broad mite control. The rate is 4.0 -8.0 qts/acre with a 0-day PHI.