Clutch (chlothianidin)- Clutch is another neonicotinyl with lepidopteran activity. Clutch will be registered with very little field efficacy data, so implementing this new insecticide into an IPM program should be done carefully.
Lepidopteran pests
Codling moth – Laboratory bioassays of Clutch against neonate larvae
indicate that although it has a fairly low LC50, it does not appear to
have the same acute toxicity as Calypso or Assail. Field trials in 2003
were disappointing with Clutch, but we are still experimenting with optimizing
the rate. If the label rate is high enough, Clutch could have the same
potential to control codling moth as Assail or Calypso.
Leafrollers – We have not tested Clutch in the field against leafrollers. However, laboratory bioassays indicate that Clutch has only low toxicity to neonate larvae.
Lacanobia fruitworm – We have not tested Clutch in the laboratory or in the field against Lacanobia.
Indirect/secondary pests
We have no tests evaluating Clutch against any of the secondary pests.
Claims about efficacy would just be speculation at this point.
Pear pests
Clutch appears to have the same activity against pear psylla and grape
mealybug as the other neonicotinyls. Trials with other neonicotinyls
suggest that the addition of oil appears to increase efficacy. The same
negative effects against campylomma as with the other neonicotinyls
should also be expected.
Use of this material against codling moth in pear comes with the same caveats as with Assail; it may be more important to direct this class of insecticides at pear psylla rather than codling moth, where there are other effective alternatives.
Beneficial arthropods
Given the efficacy against codling moth, the tendency may be to use multiple
applications in a season, however both a 2- and 4-spray program have
caused detectable mite flareups, some quite severe. At least some of
this effect is attributable to a deleterious effect on predatory mites.
This effect has been quite consistent in orchards with previous history
of mite problems, thus risk of mite disruption is rated high in such
areas. However, risk is mitigated if only a single application is made
to an orchard with a stable mite situation. The addition of 1% oil to
an Assail spray (the oil itself is miticidal) may help to reduce mite
flare-ups in some, but not all, situations. The cumulative effect of
multiple neonicotinyl applications for multiple years is unknown,
but elevated risk is probable.