Scaffolds 00 index

(Art Agnello ama4@nysaes.cornell.edu, Entomology, Geneva)

A few of our usual arthropod pests have been slightly less troublesome than normal this season, probably because of various (i.e., all conceivable) weather irregularities, but the show isn't over just yet, and this would be a good time to take some next-to-last looks at potential trouble-makers before they have the chance to take us by surprise. In no particular order, we have:

Apple Maggot - Catches have been light all around the region, but this first week in August has historically been the time for peak flight, and the soil is certainly soft enough to allow a normal emergence by whatever size population happened to make it through last summer. Be very diligent in checking any traps you have out, because we're getting indications that there could be a flush of adults coming soon.

Apple maggot volatile-baited sphere trap

Codling Moth - The model for 2nd generation codling moth larvae predicts that a control spray should be applied in problem orchards 1260 DD (base 50°F) after the start of the FIRST flight (5/19 in Geneva, 5/8 in the Hudson Valley). As of today, 8/7, 1196 DD have accumulated in Geneva. The window for the Hudson Vaylley occurred during the last week in July, but an OP application in problem orchards in western N.Y. is still a worthwhile option if no maggot sprays have been put on.

Spotted Tentiform Leafminer - Although we're past the prime control window of 690-1150 DD (base 43°F) since the start of the 2nd flight, trees with more than 2 sapfeeding mines per leaf might still benefit from an application of a material such as Vydate or Provado, particularly to forestall the possibility of a severe 3rd brood attack.

Tissue feeding mines caused by later spotted tentiform leafminer instars, visible from both sides of leaf

European Red Mite - Regardless of the low initial populations, there's still enough of the season left for ERM to build up to problem levels before harvest in sensitive varieities. Particularly in view of the warmer temperatures expected this week, a careful foliar inspection should be conducted, at least in your problem blocks, to be sure a rescue treatment of some sort isn't needed where populations surpass this month's 7.5/leaf threshold (refer to August sampling guidelines )

Leafrollers - Most growers are fairly satisfied with the program they used for taking care of the 1st summer brood of OBLR this year. However, I've been seeing some fruit damage and enough tenacious larvae to keep open the possibility that the 2nd summer brood larvae could easily become a problem in some orchards this year. The second flight should be starting in earnest by this week, which means that new larvae will be evident in favored varieties (Cortland, Idared, even Delicious) well before the end of the month. Considering the growing importance of late pre-harvest damage by the newly hatched larvae over the years, you might want to keep open the option of an eleventh-hour OBLR spray in the worst trouble spots before putting away your rig this season.

European Corn Borer - To repeat some words from an earlier issue, corn borer attack on young trees can occur from June through August. Damage to the fruit usually shows up in late summer, when the August flight of the bivoltine strain is active. Bearing orchards are more likely to show some early corn borer damage on the fruit if growers relax their spray program in June or early July. However, most fruit feeding occurs between the last cover spray (mid-August) and harvest. Weedy sites provide plenty of alternative hosts for this insect, especially those containing broadleaf dock, ragweed, pigweed, smartweed, and barnyard grass. Lannate and Lorsban can give very good control of ECB larvae, provided application is made before the caterpillars become concealed in the plant tissue. Potential problem plantings should be checked periodically in August for shoot infestations of this caterpillar, which is cream colored with a dark head.

ECB INSIDE SHOOT

Comstock Mealybug - Last week's report of CMB crawlers in tape traps turned out to be erroneous. However, don't sweat it if you applied a control spray in your pears, as this week is traditionally when they show up in WNY, and we'll be treating our own plots in a day or two ourselves. If you don't have traps out, check green shoots and cut a few pears to see whether any are showing up in the calyx. Provado is recommended for this pest, and it is also on the Diazinon pear label.

Cjomstock mealybug nymphs stuck on tape trap

Peachtree Borers - Eggs of both species are still able to hatch and get into your stone fruit trees, and this week is timely for any orchard on a seasonal control program of trunk sprays: cherries - Asana, Lorsban, Ambush, or Pounce; peaches - add Thiodan to the above list (do not spray fruit).

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