Scaffolds

Insects | Credits


SCAFFOLDS Fruit Journal, Geneva, NY                             Volume 5 
Update on Pest Management and Crop Development                 July 8, 1996

COMING EVENTS

43F 50F Current DD accumulations (Geneva 1/1-7/8): 1481 963 (Highland 1/1-7/8): 1866 1223 Coming Events: Ranges: American plum borer 1st flight subsides 848-1659 440-1098 Peachtree borer flight peaks 864-2241 506-1494 Oriental fruit moth 2nd flight peaks 1000-2908 577-2066 Lesser peachtree borer flight peaks 1095-2330 667-1526 Codling moth 1st flight subsides 1112-2118 673-1395 Lesser appleworm 2nd flight begins 1152-2302 778-1531 Obliquebanded leafroller 1st flight subsides 1420-2277 899-1546 San Jose scale 2nd flight begins 1449-1975 893-1407 Redbanded leafroller 2nd flight peaks 1479-2443 952-1698 STLM 2nd generation tissue feeders present 1504-2086 952-1201 Comstock mealybug 1st flight peaks 1528-1782 981-1185 Apple maggot 1st oviposition punctures 1566-2200 1001-1575 TRAP CATCHES (Number/trap/day) Geneva: 6/20 6/24 6/27 7/1 7/5 7/8 Redbanded Leafroller 0 0 0 0.1 0 0.3 Spotted Tentiform Leafminer 22 69 282 670 378 568 Oriental Fruit Moth 0 0 0 0.5 0.1 1.7 Lesser Appleworm 0 0 0 0 0 0.3 Codling Moth 5.8 0.9 2.0 13.6 10.6 6.7 San Jose Scale 0 0 0 0 0 0 American Plum Borer 1.5 0.4 1.0 0.6 0.1 0.5 Lesser Peachtree Borer (cherry) 0 0 0.2 0.1 0.6 0 Lesser Peachtree Borer (peach) 1.2 1.3 1.5 0.8 1.6 0.7 Peachtree Borer 3.5 5.4 9.8 7.6 4.9 5.2 Pandemis Leafroller 0.8 0.1 11.2 0.6 0.3 0.2 Obliquebanded Leafroller 1.2 0.3 0.2 0.1 0.1 1.0 Apple Maggot - 0 0 0 0 0.2* Highland (Dick Straub, Peter Jentsch) 6/3 6/10 6/17 6/24 7/1 7/8 Redbanded Leafroller 0.6 0 0 0.8 1.8 3.0 Spotted Tentiform Leafminer 0.3 1.8 55.1 24.4 1.7 33.9 Oriental Fruit Moth 1.2 1.4 0 0.6 0.4 0.9 Lesser Appleworm 0.2 0.1 0.9 0.9 0 0.2 Codling Moth 4.1 6.8 5.2 2.9 1.8 1.4 Fruittree Leafroller 0 0 0 0.1* 0 0 Tufted Apple Budmoth 0.8 0.6 0.8 1.6 1.0 1.1 Obliquebanded Leafroller 0 0.1* 4.9 1.8 2.4 2.6 Sparganothis Fruitworm 0 0.1* 0.5J 2.0 1.8 0.9 Apple Maggot - - - 0 0.2* 0.3 * = 1st catch Pest Focus Highland - Apple Maggot numbers increasing. DD (base 43F) since 1st catch of Obliquebanded Leafroller (6/10 in Highland) = 762. Spotted Tentiform Leafminer 2nd flight started 6/17; DD (base 43F) = 547 Geneva - Apple Maggot 1st catch 7/8. DD (base 43F) since 1st catch of Obliquebanded Leafroller (6/17 in Geneva) = 519. Spotted Tentiform Leafminer 2nd flight started 6/20; DD (base 43F) = 447.



STICKY FINGERS

By: Harvey Reissig & Art Agnello, Entomology, Geneva

Although the summer insects have been a bit slow to get started this year, one group that has appeared right on schedule is the green aphid complex, made up of apple aphid,Aphis pomi, and spirea aphid,Aphis spiraecola. Although small numbers of these aphids may be present on trees early in the season, populations generally start to increase in mid- to late June. Large numbers of both species build up on growing terminals on apple trees during summer, particularly when there is an abundance of succulent new foliage. Our bountiful rains over the past month have resulted in considerable new growth, which in turn has favored high aphid populations in a number of blocks. Nymphs and adults of both species suck sap from growing terminals and water sprouts. High populations cause leaves to curl and may stunt shoot growth on young trees. Aphids excrete large amounts of honeydew, which collects on fruit and foliage. Sooty mold fungi that develop on honeydew cause the fruit to turn black, reducing its quality.

Aphids should be sampled several times throughout the season starting in mid-June. Inspect 10 rapidly growing terminals from each of 5 trees throughout the orchard, and record the percentage of infested terminals. No formal studies have been done to develop an economic threshold for aphids in New York orchards, but treatment is recommended if 30% of the terminals are infested with either species of aphid. The larvae of syrphid and cecidomyiid flies prey on aphids throughout the summer. These predators complete about three generations during the summer. Most insecticides are somewhat toxic to these two predators, and they usually cannot build up sufficient numbers to control aphids adequately in regularly sprayed orchards. Both aphid species are resistant to most organophosphates, but materials in other chemical classes control these pests effectively. Some options for aphid control are Provado, Lorsban, Thiodan, or (more destructive to predator mites) Cygon, Lannate or Vydate.

COMSTOCK MEALYBUG

By: Art Agnello & Dave Kain, Entomology, Geneva

The first adult males of the season began appearing in earnest in pheromone traps late last week, so it shouldn't be long before we start seeing some adult females in pear foliage, followed by their invasive crawler offspring. According to our tests over the past few years, this is the most susceptible stage for chemical control, which we expect sometime during the next couple of weeks, especially in the Hudson Valley.

The following information is taken from the Comstock Mealybug IPM Fact Sheet, No. 22:

There are two generations of Comstock mealybug in New York, each taking 60 to 90 days to complete, depending on seasonal temperatures. The egg is generally thought to be the primary overwintering stage, but some nymphs and adult females from the second (summer) generation may also overwinter, with eggs being laid in the spring rather than the previous fall. Adult females and males emerge at the same time, from late June to mid-July for the first (overwintering) generation, and late August to mid-September for the second (summer) generation. Adult females are present for a total of 4-6 weeks, and oviposit for about one week after mating. Males survive for only a few days after emerging.

The elongate, orange-yellow eggs are laid in jumbled masses along with waxy filamentous secretions in protected places such as under bark crevices, near pruning cuts, and occasionally in the calyx of fruit. The summer-generation eggs are laid from mid-June through late July, and the overwintering eggs from mid-August into October. The early larval instars of the CMB are similar to adult females (wingless and elongate-oval in shape, with a many-segmented body) except that they are smaller, more oval-shaped, lack the long body filaments, and are orange-yellowish because they have less wax covering. Later instars are similar in appearance, but become progressively browner and redder.

The overwintered eggs hatch from mid-April through May and the nymphs (crawlers) migrate from the oviposition sites to their feeding sites on terminal growth and leaf undersides of trees and shrubs. This hatch is completed by the petal fall stage of pears. Nymphs that hatch from these overwintered eggs are active from roughly early May to early July. As the nymphs approach the adult stage, they tend to congregate on older branches at a pruning scar, a node, or at a branch base, as well as inside the calyx of pears. Second- (summer) generation nymphs are present from about mid-July to mid-September.

The Comstock mealybug poses two major concerns for the pear processing industry of New York: First, the emergence of crawlers and adult females from the calyx of pears at the packinghouse creates a nuisance to workers. Second, pears to be made into puree typically are not peeled or cored by New York processors, so infestations can potentially result in unacceptable contamination of the product.

Another problem, of concern to apple growers in the 1930s and 1940s, and again in the Hudson and Champlain Valleys in the early 1980s, is that the honeydew secreted by the crawlers is a substrate for sooty molds growing on the fruit surface. This problem also occurs on peaches in Ontario, Canada. These molds result in a downgrading of the fruit, and are therefore an additional cause of economic loss.

To date, the Comstock mealybug has been a problem to growers of processing pears because of the contamination and aesthetic reasons noted. An infestation generally requires one or more insecticide sprays during the growing season, directed against the migrating crawlers. Examine the terminal growth for crawler activity periodically throughout the summer. Crawler and adult female activity can also be monitored by wrapping black electrical or white carpet tape around low scaffold branches and inspecting for crawlers that have been caught by the tape. They can be recognized with a hand lens or, with some experience, by the unaided eye.

Sometime in early August, when we detect crawlers in some problem blocks we are monitoring, we'll advise an application of a material such as Penncap-M, Provado, Diazinon, Lannate, or (on apples only) Lorsban to control this insect.

MODEL PEST

The typical summer temperatures have moved some of the earliest OBLR sites into the 600+ DD window that we recommend in blocks that are being scouted for purposes of deciding on a control treatment. The OBLR developmental totals we've calculated as of this morning, 7/8, are given below; note that the peak hatch rate (25% of total) is predicted at 450 DD; 50% hatch comes at 630 DD, and 720 DD marks the median development point of the earliest emerging larvae:

Highland - 762 Albion - 639.3 Sodus - 603.4 Lyndonville (with last 4 days estimated): - 550 Williamson - 524.6 Appleton - 499.8 Geneva - 519



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
Department 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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