Scaffolds 01 index

(Art Agnello, ama4@nysaes.cornell.edu & Harvey Reissig, whr1@nysaes.cornell.edu, Entomology, Geneva)

Arthropod pests during the early season are not terribly numerous, but they do require some form of strategy–think of it as triage–to properly attend to the worst offenders and avoid wasting time on the lightweights. They include mites, rosy apple aphid, tarnished plant bug, and spotted tentiform leafminer. The key behind all of them depends, at least in part, on being familiar with your own orchards – does a given block have a history of or susceptibility to a specific pest? Start with your knowledge of the block, use a sampling procedure where appropriate, and make a management decision.

Mites

If you're not electing a delayed-dormant oil application as a part of your early season mite management program, you'll be needing to rely on either: one of the ovicidal acaricides (Apollo, Savey) available for use, whether before or after bloom; a rescue-type product (Pyramite, Kelthane, Carzol) that can reduce motile numbers if they should begin to lap at the threshold; or Agri-Mek, which falls somewhere between these two strategies. Please note that, while Apollo has a post-bloom label with a 45-day PHI, the comparable registration for Savey has yet to be approved in NY, so it's still showing a last use at pink bud stage, until we hear otherwise. Like the true ovicides, Agri-Mek should also be considered a preventive spray, since it needs to be applied early (before there are very many motiles) to be most effective, generally within the first 2 weeks after petal fall. Also, as a reminder, Carzol is now restricted to no later than petal fall, so it will probably be of limited use in most programs. For any of the rescue products, the operational threshold in June is an average of 2.5 motiles per leaf (see the chart on p. 60 of the Recommends).

Rosy Apple Aphid

Rosy apple aphid (RAA) will attack all apple varieties, but those such as Cortland, Monroe, R.I. Greening, Idared, and Golden Delicious are particularly susceptible, and those in the McIntosh family are relatively tolerant.

Our control recommendations for RAA cover the period from half-inch green to the pink bud stage, using any of a number of materials: Thiodan, Lorsban, Lannate, Vydate, Supracide, Danitol or Asana, listed roughly in order of increasing disruption of beneficial mites. Pink applications of any of these products do a better job than an earlier spray. This is an observation resulting from the fact that, in those cases where aphid populations have built up during early summer on vegetative growth inside the canopy, a pink spray will have done a more effective job of reducing populations than an earlier treatment at half-inch green. From the standpoint of management practicality, it is therefore easier and more natural to consider the need for aphid control at the time of the pink spray. Provado is an excellent RAA material, but it can be applied no earlier than petal fall, by which time much of the fruit damage this insect causes already will have been initiated.

RAA nymphs are of course present at Pink, and large enough to see without difficulty, but they do occur on the same tree and in the midst of colonies of green apple aphids, which are not usually a problem until the summer. To distinguish among the species, you can use leaf damage as a cue, as well as the insects' color. RAA nymphs are usually pinkish, sometimes varying to a light brown, slate gray, or greenish black, and the body is covered with a whitish mealy coating. Most importantly, they have pronounced cornicles ("tailpipes"), and long antennae (more than half the body length). Green apple aphid nymphs are clearly green, and without the whitish cast. Their cornicles are little more than buttons, and the antennae are clearly less than half of the body length. Also, aphids found inside curled or distorted leaves at pink are almost always rosy apple aphids. If you find ONE infested cluster (1%, or stop as soon as you find one), we would advise including an RAA material in your pink spray; this threshold may be a little conservative for people who are skilled at finding the aphids.

Spotted Tentiform Leafminer

What else is happening at pink? STLM is laying eggs, but most orchards don't suffer too greatly from 1st brood leafminer, and even if so, a sequential sampling plan can be used to classify STLM egg density at pink or of sap-feeding mines immediately after petal fall (see p. 57 in the Recommends).

Treatment is recommended if eggs average 2 or more per leaf on the young fruit cluster leaves at pink, or if sap-feeding mines average 1 or more per leaf on these leaves at petal fall. Sampling can be completed in approximately 10 minutes. In recent years, only 1 out of 6 sampled orchards have required insecticide treatments to control first-generation STLM populations. Vydate at pink or Provado or Lannate at petal fall are our standard recommendations for this pest; Provado will also add to the leafhopper control if you don't use enough Sevin at thinning to do an adequate job.

Miscellaneous

Leafrollers are also out there, but only part of the population is active at this time, so it's better to wait for bloom or petal fall to address this one. Tarnished plant bug is the only real player left, and you're going to have to decide for yourself whether this bug is a major concern to you. We have seen few orchards in western N.Y. where TPB control is warranted (slightly more so in the Hudson Valley), simply because the most effective treatment to use is still a pyrethroid, which a) wipes out predator mites, and b) still rarely lowers TPB damage enough to be economically justified.

If you elect a spray of Ambush, Asana, Danitol or Pounce at pink for plant bug, you'll take care of rosy apple aphid (and STLM) at the same time; if rosies are your primary concern, scout for them first, and use Lorsban or Thiodan if you find any.

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