In most orchards monitored with sticky red rectangle trunk traps, cumulative trap captures remain at 0-2 leafminers per trap. However, in one orchard trap captures have exceeded 20 leafminers per trap, signifying a high population in need of treatment. We do not recommend use of either of these chemicals due to their negative effect on predatory mite populations. Both Provado and Agrimek are safe on mite predators. Experience in Massachusetts in 1996 indicated that a Provado application at petal fall was much more effective against first generation leafminers than a late June spray of Provado against the second generation.
Predators ought to be the foundation upon which all other mite management tactics are built.
In New England, we have at present only one truly effective mite predator, Amblyseius fallacis, that is widespread throughout the region. Unfortunately, cold weather during winter usually takes a heavy toll on A. fallacis, reducing it to low numbers by spring. Rarely does it build sufficiently to provide effective biocontrol until late July. At present, only a few New England orchards are blessed with detectable numbers of the predator Typhlodromus pyri, which is capable of providing excellent season-long biocontrol of mites, even during spring and early summer. Some orchards in every New England state are currently being seeded with T. pyri.