Diamond (Novaluron/difluorobenzamide)-
Diamond is the next generation of benzoyl urea growth regulators, in the
same class as Dimilin. Although similar to Dimilin in its targets and
mode of action, we believe that Diamond is more active than Dimilin against
those same pests. Diamond inhibits chitin synthesis and embryogenesis,
which makes its mode of action unique compared to Intrepid or Esteem.
Diamond’s primary target is the egg stage, however it is also effective
against early instar pear psylla.
Lepidopteran pests
Codling moth- We believe the primary target of Diamond is against the codling
moth egg. Evaluations of field-aged residues indicated Diamond was causing
more than 90% suppression of egg hatch 35 days after application. Field
trials indicated that a season-long Diamond program (3 applications/generation)
reduced codling moth fruit injury 85-95% relative to the untreated control.
In these trials, Diamond was applied prior to the onset of oviposition
(75 DD) with repeat applications at 14-day intervals. Second generation
applications began at 1000 DD. Diamond is probably the best ovicidal
alternative currently available for summer use.
Leafroller- We have not evaluated Diamond against leafrollers in field trials. Laboratory bioassays indicated that Diamond had very little activity against leafroller neonates. These results were corroborated with field-aged residue tests, which indicated little or no activity of even 1-day-old residues. We believe the primary activity of Diamond against codling moth is ovicidal, however we have not evaluated the ovicidal activity against leafroller.
Lacanobia fruitworm- We have not evaluated Diamond against Lacanobia in field trials. However, laboratory bioassays indicated that Diamond is highly toxic to Lacanobia neonates. Field-aged residue tests indicate a breakdown in efficacy after 21 days from application.
Indirect/secondary pests
Diamond has no known effect on mites, aphids, campylomma, scale, or leafhopper.
It is possible that there would be effects against leafminer, however
we have not verified this with field trials.
Pear pests
Diamond has the same spectrum of activity against pear pests as Dimilin,
but at a higher level. Diamond is active against pear psylla, acting
primarily against the eggs and early instars. Diamond has been found
effective when applied against the first generation of pear psylla. The
clusterbud timing optimizes the efficacy of Diamond as the population
is made up of eggs and newly hatched nymphs at that time. When using
Diamond in a pear psylla program it is helpful to use products such as
Surround, Thiodan, sulfurs, and oil, which when used at delayed dormant
help to reduce the pest pressure and better synchronize the generation.
Diamond is also effective shen used during the summer; however, the level
of effectiveness is decreased as more and larger instars become present
in the developing populations.
Codling moth is another target pest for Diamond applications in pear. Diamond should control low-moderate populations of codling moth, with results similar to chloronicotinyls. If other control tactics are being used (e.g mating disruption or larvicidal insecticides) Diamond will be an effective tool in high pressure situations as well. There is concern that codling moth populations resistant to organophosphates may also be tolerant or resistant to Diamond due to OP mediated cross-resistance. This may lead to variability in observed efficacy.
Beneficial arthropods
Since Diamond is a relatively new insecticide, we have little experience
against beneficial arthropods. Our experience with growth regulators
is that they are not acutely toxic to beneficial arthropods, however
there is concern about sublethal effects, especially on fertility of
adults exposed to residues.