RI Apple IPM Newsletter
April 26, 1999
From Heather Faubert and Steve Alm
The recorded pest message is operating now. Call (401) 949-0670
between 5:00PM and 8:00AM for the weekly recorded message. New messages
are recorded on Wednesdays.
Our first apple scab infection period of the season occurred on
April 22-23. Hopefully everyone's trees were either protected with a fungicide
or used a fungicide with kick back action within an appropriate amount.
Apple blotch leafminers have been caught on red sticky traps attached
to trunks since April 9. The threshold of 8 leafminers per trap by tight
cluster has been exceeded in 9 out of 11 orchards. In five of these orchards
we have an average of over 100 leafminers per trap. For some reason leafminer
populations are extremely high this year! On one leaf I found 21 leafminer
To control leafminers we recommend applying Provado or Agri-Mek at petal
fall. Agri-Mek must be mixed with an adjuvant to be effective. It seems
an oil spray, such as Sunspray Ultrafine Oil, is more effective with the
Agri-Mek than a spreader sticker such as LI-700 or Silwet. Of course,
combining Agri-Mek with oil causes complications when using Captan. Don't
use Captan within two weeks of an oil application.
Provado used at petal fall will also control white apple leafhopper and
rosy apple aphid. Agri-Mek used at petal fall will also contol European
European red mites should be hatching by now but as of 4/26/99
I did not find any hatched eggs. There is still time to apply dormant
oil to suffocate red mite eggs. After tight cluster, oil should be applied
at 1 gal/ 100 gal. Apollo or Savey can be used for mite control only
if you did not use one of those miticides last year. Red mites can easily
build up resistance to these materials so it is recommended to not
use them any more frequently than once every other year. The same is true
for Agri-Mek. If you used it last year, don't use it this year.
Look now through pink for rosy apple aphids. Rosy apple aphids
will attack all apple varieties, but varieties such as Cortland, Ida Red,
Golden Delicious are particularly susceptible, and those in the McIntosh
family are relatively tolerant. Rosy apple aphids are usually pinkish,
sometimes varying to light brown, slate gray, or greenish black. The body
is covered with a whitish coating. Don't confuse them with harmless green
apple aphids. Green apple aphid nymphs are clearly green, and without
the whitish cast. Also, aphids found inside curled or distorted leaves
at pink are almost always rosy apple aphids.
Sample 10 clusters from the interior of susceptible trees; sample 10 trees
per block. If you find even one rosy apple aphid it is recommended to
apply an insecticide at pink. Thiodan or Lorsban at pink will control
rosy apple aphid. Synthetic pyrethroids (such as Pounce or Asana) are
also effective but we do not recommend them since they are so harmful
to predatory mites. Provado used at petal fall will also control rosy
apple aphid but Thiodan or Lorsban at petal fall will not control rosy
apple aphid sufficiently.
Included is an update of the New England Apple Pest Management Guide.
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