Tree Fruit Research & Extension

New Insecticides for Apple and Pear IPM

Actara (thiamethoxam) – Actara is a closely related compound to Provado. Its activity and use is much the same as Provado, with the same target pests and ‘transtemic’ activity. Do not use Actara 5 days prior to placing bees in orchard and while bees are in the orchard, and exercise caution when bees are in neighboring blocks, especially if there are blooming weeds in the orchard. As of 2004, Actara was no longer available for use in apple.

Lepidopteran pests
Codling moth – We have not tested Actara against codling moth. It is not expected to have activity against any Lepidoptera.

Leafrollers – See comments under codling moth.

Lacanobia fruitworm – See comments under codling moth.

Indirect/secondary pests
Note that Actara is no longer available in Apple (2004). Two year's tests on campylomma have demonstrated good efficacy against this pest, even though it cannot be used during bloom (pink would be the preferred timing). Actara is effective against the green aphid complex, and offers some suppression of woolly apple aphid and rosy apple aphid (limited data). There is no evidence of useful activity against leafminer. Actara is also a good leafhopper material.

Pear pests
Actara has much the same activity against pear psylla and grape mealybug as Provado. Like Provado, Actara is effective against the early instars of both of these pests (first and second instars of pear psylla, ‘soft-shell’, and second and third instars of grape mealybug, ‘crawlers’). Effectiveness against older instars of these pests is greatly reduced, and there is relatively little activity against adults. Using oil as an adjuvant to Actara has been demonstrated to increase mortality of pear psylla and grape mealybug.

Actara, unlike Provado, is registered for prebloom use in pear. It should not be applied later than clusterbud when used prebloom, to avoid any potential for effects on bees. The clusterbud timing is very effective in controlling both pear psylla and grape mealybug. In typical years, this period is when peak pear psylla egg hatch is occurring, and the age distribution is limited to first and second instar nymphs, as well as adults and eggs. Actara applications will cause mortality to the nymphs, and residual activity will continue to control hatching eggs. This period is also when grape mealybug have peak emergence from egg masses. Actara is very effective against the second instar crawlers that become exposed at this time.

Actara can also be effective in petal fall applications, as with Provado, provided the pear psylla and grape mealybug are of the appropriate stage. Actara is at least equal in efficacy to Provado when used against summer generations of both pear psylla and grape mealybug. Oil is an effective adjuvant for Actara. Summer applications of Actara have negative effects on the biocontrol agent campylomma; care should be taken to avoid impacting populations of this important beneficial.

Beneficial arthropods
Actara does not appear to be directly toxicity to predatory mites, thus the overall risk of mite disruption is currently rated low. Do not use Actara where bee exposure is possible.

Tree Fruit Research & Extension Center, 1100 N. Western Ave, Wenatchee, WA, 509-663-8181, Contact Us