Scaffolds


A FINAL MITE

By:Art Agnello, Entomology, Geneva

I'm not sure how commonly N.Y. growers encounter the pearleaf blister mite, Phytoptus pyri, but on the assumption that a year as extreme as this one can bring out the worst of even lesser-known mite pests, I thought it might be worth mentioning. This is a sporadic pest of pears that does not normally show up in commercial pear orchards, but is a fairly common problem in home plantings. The adults are very small and cannot be seen without a hand lens; the body is white and elongate oval in shape, like a tiny sausage. The mite causes three distinct types of damage. During winter, the feeding of the mites under the bud scales is believed to cause the bud to dry and fail to develop. This type of damage is similar to and may be confused with bud injury from insufficient winter chilling. Fruit damage is the most serious aspect of blister mite attack. It occurs as a result of mites feeding on the developing pears, from the green-tip stage through bloom, causing russet spots. These spots, which are often oval in shape, are usually depressed with a surrounding halo of clear tissue. They are 1/4-1/2 inch in diameter and frequently run together. A third type of injury is the blistering of leaves; blisters are 1/8-1/4 inch across and, if numerous, can blacken most of the leaf surface. Although defoliation does not occur, leaf function can be seriously impaired by a heavy infestation.

The mite begins overwintering as an adult beneath bud scales of fruit and leaf buds, with fruit buds preferred. When buds start to grow in spring, the mites attack developing fruit and emerging leaves. This produces red blisters in which female blister mites then lay eggs. These resulting new colonies of mites feed on the tissue within the protection of the blister, but can move in and out through a small hole in its center. The mites pass through several generations on the leaves but their activity slows during the warm summer months. The red color of the blisters fades and eventually blackens. Before leaf fall the mites leave the blisters and migrate to the buds for the winter.

A fall spray is recommended sometime in October, when there is no danger of frost for at least 24-48 hr after the spray. Use Sevin 50 WP (2 lb/100), or 1-1.5% oil plus either Diazinon 50WP (1 lb/100 gal) or Thiodan 50WP (1/2-1 lb/100 gal). A second spray of oil plus Diazinon or oil plus Thiodan, in the spring, just before the green tissue begins to show, will improve the control.

WAS 1995 "NORMAL"?

By:Dave Kain & Art Agnello, Entomology, Geneva

Over the years, in our feeble attempt to understand what's going on out there, information on the occurrence of insects that affect crops is collected and compared against something that we can understand, like the calendar or degree days. These data are then sorted, collated and analyzed to produce averages that we presumptuously call "normal". It's interesting, and possibly useful, to know how far and in which direction from "normal" a particular event falls. As with our recollections of the year's weather, we're often surprised when we see our perceptions compared with hard data. Keeping this in mind, we would like to compare some of the pest events that occured this season (in Geneva) with those normals. (In alphabetical order, of course.)


EVENT

DATE DEGREE DAYS (BASE 43F) ______________________ ____________________ Normal (+/-days) 1995 Normal (+/-DD) 1995 APPLE MAGGOT 1st catch 28-Jun (+/-8) 26-Jun 1336 (+/-168) 1276 Peak 3-Aug (+/-15) 27-Jul 2354 (+/-194) 2172 Subsiding 5-Sep (+/-11) 31-Aug 2984 (+/-148) 3177 1st oviposition punctures 18-Jul (+/-7) 28-Jul 1803 (+/-275) 2200 AMERICAN PLUM BORER 1st catch 18-May (+/-7) 15-May 425 (+/-120) 406 1st flight peak 2-Jun (+/-6) 1-Jun 684 (+/-147) 692 1st flight subsiding 28-Jun (+/-7) 29-Jun 1338 (+/-217) 1355 2nd flight start 10-Jul (+/-3) 6-Jul 1587 (+/-261) 1546 2nd flight peak 27-Jul (+/-6) 31-Jul 2183 (+/-241) 2292 2nd flight subsiding 13-Sep (+/-8) 7-Sep 3326 (+/-222) 3339 CODLING MOTH 1st catch 18-May (+/-7) 17-May 479 (+/-106) 439 1st flight peak 3-Jun (+/-12) 1-Jun 769 (+/-195) 692 2nd flight start 17-Jul (+/-14) 29-Jun 1843 (+/-350) 1355 2nd flight peak 10-Aug (+/-8) 7-Aug 2475 (+/-369) 2514 2nd flight subsiding 10-Sep (+/-8) 18-Sep 3142 (+/-237) 3514 COMSTOCK MEALYBUG - Adult males 1st catch 1-Jul (+/-4) 28-Jun 1448 (+/-136) 1460 1st flight peak 8-Jul (+/-5) 7-Jul 1639 (+/-82) 1727 1st flight subsiding 20-Jul (+/-10) 18-Jul 1983 (+/-137) 2053 COMSTOCK MEALYBUG - Crawlers 1st catch 3-Aug (+/-12) ND 2344 (+/-119) - Peak 6-Aug (+/-15) ND 2502 (+/-122) - EUROPEAN RED MITE - Overwintered eggs Hatch starts 6-May (+/-4) 8-May 284 (+/-55) 290 GREEN FRUITWORM 1st catch 4-Apr (+/-9) 27-Mar 79 (+/-28) 111 Peak 15-Apr (+/-11) 4-May 140 (+/-62) 255 Subsiding 5-May (+/-10) 17-May 310 (+/-92) 439 LESSER APPLEWORM 1st catch 11-May (+/-10) 1-May 392 (+/-155) 230 1st flight peak 23-May (+/-8) 15-May 599 (+/-193) 406 1st flight subsiding 20-Jun (+/-11) 19-Jun 1185 (+/-266) 1055 2nd flight begins 10-Jul (+/-18) 22-Jun 1623 (+/-492) 1152 2nd flight subsiding 28-Sep (+/-14) ND 3308 (+/-145) ND LESSER PEACHTREE BORER 1st catch 26-May (+/-8) 25-May 588 (+/-155) 563 Flight peak 5-Jul (+/-17) 20-Jun 1486 (+/-434) 1095 Flight subsiding 10-Sep (+/-8) 18-Sep 3140 (+/-192) 3514 OBLIQUEBANDED LEAFROLLER 1st catch 11-Jun (+/-5) 12-Jun 917 (+/-86) 911 1st flight peak 20-Jun (+/-8) 19-Jun 1163 (+/-195) 1055 2nd flight begins 7-Aug (+/-10) 31-Jul 2500 (+/-181) 2292 2nd flight peak 21-Aug (+/-13) 21-Aug 2882 (+/-191) 2943 ORIENTAL FRUIT MOTH 1st catch 2-May (+/-6) 4-May 300 (+/-99) 255 1st flight peak 13-May (+/-11) 17-May 418 (+/-93) 439 2nd flight begins 2-Jul (+/-6) 22-Jun 1441 (+/-162) 1152 2nd flight peak 8-Jul (+/-11) 29-Jun 1778 (+/-451) 1355 3rd flight begins 12-Aug (+/-10) 27-Jul 2594 (+/-251) 2172 3rd flight peak 24-Aug (+/-11) 3-Aug 2912 (+/-317) 2389
PEAR PSYLLA 1st adult 31-Mar (+/-14) 27-Mar 64 (+/-36) 111 1st oviposition 5-Apr (+/-11) 27-Mar 82 (+/-45) 111 1st nymphs 1-May (+/-5) 1-May 241 (+/-71) 230 PEACHTREE BORER 1st catch 17-Jun (+/-11) 1-Jun 1061 (+/-290) 692 Flight peak 10-Jul (+/-21) 8-Jun 1666 (+/-515) 864 Flight subsiding 26-Aug (+/-13) 24-Aug 2876 (+/-296) 3020 REDBANDED LEAFROLLER 1st catch 18-Apr (+/-7) 24-Apr 185 (+/-87) 186 1st flight peak 4-May (+/-9) 15-May 298 (+/-85) 406 2nd flight begins 3-Jul (+/-6) 6-Jul 1515 (+/-225) 1546 2nd flight peak 14-Jul (+/-7) 21-Jul 1783 (+/-328) 1988 2nd flight subsiding 5-Aug (+/-11) 27-Jul 2383 (+/-258) 2172 3rd flight begins 20-Aug (+/-12) 3-Aug 2758 (+/-208) 2389 3rd flight peak 29-Aug (+/-15) 7-Aug 2852 (+/-239) 2514 SAN JOSE SCALE - adult males 1st catch 16-May (+/-8) 15-May 475 (+/-116) 406 1st flight peak 31-May (+/-7) 1-Jun 675 (+/-56) 692 2nd flight start 15-Jul (+/-10) 6-Jul 1686 (+/-203) 1546 2nd flight peak 14-Aug (+/-10) 10-Aug 2392 (+/-210) 2591 2nd flight subsiding 29-Aug (+/-12) 24-Aug 2857 (+/-305) 3020
SPOTTED TENTIFORM LEAFMINER 1st catch 19-Apr (+/-7) 20-Apr 175 (+/-67) 158 1st flight peak 5-May (+/-6) 17-May 313 (+/-75) 439 2nd flight begins 14-Jun (+/-7) 22-Jun 1067 (+/-134) 1152 2nd flight peak 10-Jul (+/-8) 17-Jul 1681 (+/-225) 1872 2nd flight subsiding 27-Jul (+/-9) 7-Aug 2220 (+/-235) 2514 3rd flight begins 8-Aug (+/-8) 14-Aug 2531 (+/-170) 2710 3rd flight peak 23-Aug (+/-10) 24-Aug 2878 (+/-207) 3020 3rd flight subsiding 12-Sep (+/-7) 18-Aug 3311 (+/-96) 3514

CROP PHENOLOGY

DATE DEGREE DAYS (BASE 43F) ______________________ ____________________ Normal (+/-days) 1995 Normal (+/-DD) 1995 APPLE-MCINTOSH Silver tip 9-Apr (+/-8) 13-Apr 84 (+/-29) 137 Green tip 11-Apr (+/-6) 17-Apr 108 (+/-42) 140 Half-inch green 21-Apr (+/-7) 24-Apr 176 (+/-29) 186 Tight cluster 27-Apr (+/-6) 4-May 228 (+/-24) 255 Pink 3-May (+/-6) 11-May 295 (+/-30) 320 Bloom 9-May (+/-6) 17-May 377 (+/-40) 439 Petal fall 17-May (+/-5) 25-May 494 (+/-51) 563 PEACH Swollen bud 15-Apr (+/-4) 13-Apr 126 (+/-38) 137 Bud burst 22-Apr (+/-4) 17-Apr 136 (+/-5) 140 Half-inch green 27-Apr (+/-7) 1-May 186 (+/-29) 230 Pink 28-Apr (+/-9) 4-May 215 (+/-31) 255 Bloom 5-May (+/-6) 11-May 298 (+/-58) 320 Petal fall 12-May (+/-9) 17-May 406 (+/-123) 439 PEAR Swollen bud 14-Apr (+/-5) 17-Apr 123 (+/-42) 140 Bud burst 23-Apr (+/-7) 20-Apr 159 (+/-52) 158 Green cluster 1-May (+/-5) 4-May 240 (+/-30) 255 White bud 5-May (+/-7) 11-May 297 (+/-53) 320 Bloom 8-May (+/-7) 15-May 344 (+/-50) 406 Petal fall 15-May (+/-8) 22-May 436 (+/-57) 511 PLUM Swollen bud 17-Apr (+/-8) 24-Apr 148 (+/-38) 186 Bud burst 27-Apr (+/-4) 27-Apr 173 (+/-49) 201 Green cluster 1-May (+/-5) 4-May 239 (+/-35) 255 White bud 5-May (+/-5) 8-May 239 (+/-17) 290 Bloom 7-May (+/-5) 11-May 329 (+/-49) 320 Petal fall 13-May (+/-5) 17-May 393 (+/-53) 439
SWEET CHERRY Swollen bud 12-Apr (+/-5) 13-Apr 100 (+/-32) 137 Bud burst 23-Apr (+/-6) 20-Apr 177 (+/-30) 158 White bud 1-May (+/-6) 4-May 222 (+/-31) 255 Bloom 5-May (+/-6) 8-May 267 (+/-36) 290 Petal fall 13-May (+/-4) 17-May 383 (+/-61) 439 TART CHERRY Swollen bud 15-Apr (+/-6) 13-Apr 117 (+/-61) 137 Bud burst 27-Apr (+/-6) 24-Apr 210 (+/-42) 186 White bud 9-May (+/-5) 8-May 281 (+/-26) 290 Bloom 11-May (+/-4) 15-May 365 (+/-59) 406 Petal fall 18-May (+/-4) 25-May 462 (+/-65) 563


Scaffolds is published weekly from March to September by Cornell University -- NYS Agricultural Experiment Station (Geneva), and Ithaca -- with the assistance of Cornell Cooperative Extension. New York field reports welcomed. Send submissions by 3 p.m. Monday to:

Scaffolds Fruit Journal
Editors: A. Agnello, D. Kain
Dept. of Entomology, NYSAES
Geneva, NY 14456-0462
Phone: 315-787-2341 FAX:315-787-2326
E-mail: art_agnello@cornell.edu

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