Scaffolds 99 index

1999 TREE FRUIT ARTHROPOD PEST REVIEW (W.N.Y.)

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

This season had many of the same characteristics as those that marked last year's fruit-growing adventure, minus the devastating Labor Day storm, so it's not strange to note that the resulting insect and mite situations were also quite similar to those of 1998. Early, hot, and dry, seem to be the best words to describe this season, and the effects of this type of weather on our arthropod pests were generally predictable. It should be stated, first of all, that this year we saw one of the most pleasant, mild, textbook examples of a favorable N.Y. spring season that I can recall. No interminable stormy periods of rain or wind, no breathtaking jumps backward into wintry gloom, just a modest, very gradual warming trend that gave growers some of the best possible conditions for executing their early season control programs. Most people even seemed ready for the heavyweight hot temperatures when they arrived in mid-June, just not for the utter lack of rain we received (and *we* made out much better than our neighbors to the south).

European red mite adult female

One of the most pleasant surprises of this season concerned the situation with European red mite control. Despite the kind of weather patterns that excel at creating mite explosions, very few reports or instances of problem mite populations were heard or seen this year. We are assuming that one or two contributing factors are responsible for this situation: Apparently, most growers had ample opportunity to put on early season oil/Apollo/Savey, etc. applications, and therefore many potential problems were taken care of before they developed. Secondly, we seem to be in the midst of that rarest of circumstances – a period when there are several very effective miticides available, and they all seem to be working at their best. Remember just a few years ago, when it seemed as though there would never be any more new products labelled for mite control? And, it looks like several more new ones are in the wings for introduction soon, as each of the major agrichemical companies appear to have their own new entry into this field. To be fair, we did still have some problems with twospotted spider mites moving in later in the season, so we are awaiting some developments in rescue materials that can better address this weak area in our toolbox.

Spotted Tentiform Leafminer Adult

Spotted tentiform leafminer is one pest that did cause problems in some localized orchards, as this was the kind of weather that favors their success. Infestations of the first brood were noticeable, if not always serious, and the second and third broods caused problems in some blocks where preventive measures were not followed. Some other early season pests that didn't seem to develop into much of a concern were rosy apple aphid, plum curculio (shorter oviposition period this year), and pear psylla, for which we don't really have any explanation, other than the relative lack of succulent foliage because of the dry weather. This obviously was also a factor in the low green aphid populations statewide.

A reasonable person surveying the fruit damage currently evident from obliquebanded leafroller on some of the apples yet to be harvested would conclude that this year has been a pretty typical one from the viewpoint of population pressure. That is, some problem blocks have sustained damage similar to that seen in most other years. In addition, the developmental timing of the two generations was even more un-synchronized than usual, so that we were seeing large overwintered larvae as late as July, and first summer brood egg masses in August. However, two points should be noted that marked this season as being a little different for the life of a leafroller this season. First, the very dry conditions cut down on the production of terminal growth, which drove the young larvae to seek unorthodox feeding sites, mainly on the undersides of mature leaves, often up against the midvein or along the leaf edge, so that detection of foliar infestations was sometimes difficult. Also, a number of growers used a SpinTor program for management, and many expressed satisfaction with their results. We'll be looking to see if this view holds through the harvest and storage season, but if so, it would be a welcome change for the better in this perennial battle with OBLR.

Oriental fruit moth adult

Once again, codling moth and oriental fruit moth were reported to be particularly plentiful in certain areas; trap catches of adults were quite high, and fruit damage was greater than normal in some peach and apple plantings. There is increasing concern that OP resistance may be starting to show up in OFM populations in particular, a possibility that we will be addressing this fall with the help of Deb Breth and Dave Pree (at the Vineland Station). Comstock mealybug continued to make unwelcome appearances in pear and some peach orchards; we tested a new compound for control of this pest, with some favorable results, so with any luck there may be another management alternative available soon.

Apple Maggot Adult

For the third year, apple maggot once again suffered from the lack of summer rain; adult catches were down overall, but the effect was localized – some areas did see a normal flush in early August, but in many others, it was simply too dry. As before, it definitely paid off to hang traps in individual blocks to determine the need for sprays. Finally, it's a bit too early to ring down the curtain on a few of the late callers, but so far it doesn't look as though white apple leafhopper or woolly apple aphid are going to make much of a mark on this season's pest scene.

End of this issue: Scaffolds 1999 Index