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SCAFFOLDS Fruit Journal, Geneva, NY                 	Volume 4 
Update on Pest Management and Crop Development      	June 19, 1995 

COMING EVENTS

 						 43F       50F 
Current DD accumulations (Geneva 1/1-6/19):	1055       703 
			(Highland 3/1-6/19):	1163       692

Coming Events:                              	Ranges: 
American plum borer 
1st flight peak					535-962     273-601 
Codling moth 1st flight peak 			547-1326    307-824 
Cherry fruit fly 1st catch			650-1500    368-961 
Spotted tentiform leafminer 2nd flight begins   795-1379    449-880 
Obliquebanded leafroller 1st flight peak 	869-1482    506-964 
San Jose scale 1st gen crawlers present         987-1247    569-784 
Pear psylla 2nd brood hatch			992-1200    609-763 
Apple maggot 1st catch			       1045-1662    629-1078


TRAP CATCHES (Number/trap/day) 

Geneva: 
				   6/5    6/8   6/12   6/16   6/19
Spotted Tentiform Leafminer       29     25	 7.1    4.3   12.2 
Oriental Fruit Moth (apple)        0.8	  0.8    0.5    0.5      0 
Lesser Appleworm		   1.9	  1.5    0.3    0.4      0 
Codling Moth 			   5.9   11.8    6.5    4.4    5.3
San Jose Scale 			   2.3    0.2    0 0      0 
American Plum Borer (cherry)       2.4	  3.0    0.3    0.3    1.2 
Lesser Peachtree Borer (peach)     2.9    4.3	 6.0    1.9      - 
Lesser Peachtree Borer (cherry)    3.0    6.0	 3.4    0.8    4.2 
Peachtree Borer                    4.0    8.8	 4.4    3.6      -
Obliquebanded Leafroller 	   0      0      0.1*   0.1    3.3 
Pandemis Leafroller 		   0      1.0*   2.0    1.4    0.8


Highland: (Dick Straub, Peter Jentsch) 
				5/22   5/29    6/5   6/12    6/19
Redbanded Leafroller            0.6   <0.1     0      0      0 
Spotted Tentiform Leafminer 	2.6    0.5     0.9    2.9    9.1 
Oriental Fruit Moth 		0      0.5     1.1    1.4    0 
Fruittree Leafroller            0      0       0      0.3    0 
Codling Moth 			1.9    4.6     4.9    3.5    1.1 
Lesser Appleworm		1.0*  <0.1     0      0      0 
Sparganothis Fruitworm 		0      0       0.1*   1.1    3.0 
Tufted Apple Budmoth 	       <0.1*   1.1     1.4    1.0    1.6 
Variegated Leafroller           0      0       0      0.5*   0.6 
Obliquebanded Leafroller	0      0       0      0.8*   1.6 
						   * = 1st catch

PEST FOCUS 

Geneva: 

     Obliquebanded Leafroller catch increasing.  DD (base
          43) since 1st catch = 145. 

     White Apple Leafhopper and Potato Leafhopper adults present. 
	
Highland: 

     Obliquebanded Leafroller catch increasing.  DD
          (base 43) since 1st catch = 163.
           
     Spotted Tentiform Leafminer 2nd flight began, 6/12. 
          DD (base 43) since 1st catch = 163. 

     White Apple Leafhopper and Rose Leafhopper adults observed. 

     High numbers of Green Apple Aphids and Spirea Aphids observed. 

DISEASES

FABRAEA ON PEARS

By:Dave Rosenberger, Plant Pathology, Highland
Hot, humid weather with intermittent rains or dews favors development of Fabraea leaf spot and fruit spot on pears. The critical season for protecting pears from Fabraea begins during late June and early July. Most commercial problems that I have seen in the past have surfaced shortly after the Fourth of July, when the disease suddenly "explodes" in certain blocks. It is unclear whether the July 4th timing of symptom development is associated with spore releases or with the common grower practice of stretching spray intervals after the scab season ends in June.

Fabraea appears as small, round, purplish leaf spots. The first spots usually develop on leaves sometime after petal fall. Very few growers or fieldmen recognize the early infections because the first leaf spots are usually present in very limited numbers and are rather nondescript. Each of these initial infections, however, can produce millions of slimy spores that are disseminated by splashing rain or by pear psylla and other insects. If spores are disseminated by insects, infection can occur during long dew periods in the absence of rain. Economic damage is usually caused by the rapid development of secondary infections in orchards where primary infections became established in June. If fungicide protection is lacking or inadequate, fruit can become severely infected during July and August. Severely infected Bosc trees can lose most of their leaves by late August.

Fabraea is relatively easy to control if fungicides are applied before the disease reaches epidemic proportions in an orchard. Mancozeb is the most effective fungicide for Fabraea, but it cannot be used within 77 days of harvest. (Mancozeb used at petal fall, first and second cover can help prevent the primary infections that provide inoculum for disease development during July.) Ziram is probably the best fungicide for controlling spread of Fabraea during summer. (Captan is not labeled for pears.) Benlate has been effective in some trials and ineffective in others. Ziram applied on a three-week interval will provide adequate protection, except when heavy rains remove fungicide residues or when the disease was well established before the first spray was applied. Ziram coverage may need to be renewed after 1.5-2.0 inches of rain. Where disease pressure is very high (i.e., early infections were not controlled), sprays may need to be applied on a 14-day interval. As with summer diseases on apples, good spray coverage is essential for controlling this disease. After spots become abundant on leaves, it is virtually impossible to stop the epidemic, and the fruit will almost certainly be severely affected by Fabraea spot.

BENEFICIAL INSECTS

By:Art Agnello, Entomology, Geneva
There are many insects present in apple orchards that provide a benefit to growers by feeding on pest species. It is important that growers be able to recognize these beneficial insects, so that they are not mistaken for pests. The best way to conserve beneficial insects is to spray only when necessary, and to use materials that are less toxic to them (see Tables 8 & 12, pp. 37 and 43 of the 1995 Recommends). This brief review, taken from IPM Tree-Fruit Fact Sheet No. 18, covers the major beneficial insects that are likely to be seen in New York orchards, concentrating on the most commonly seen life stages. Newly released factsheet No. 23, "Predatory Mites", reviews mites that are important predators of leaf-feeding mites.

CECIDOMYIID LARVAE (Aphidoletes aphidimyza)

This fly (Family Cecidomyiidae) is an aphid predator, and overwinters as a larva or pupa in a cocoon. Adults emerge from this cocoon, mate, and females lay eggs among aphid colonies. The adults are delicate, resembling mosquitoes, and are not likely to be seen. The eggs are very small (about 0.3 mm or 1/85 in. long) and orange. They hatch into small, brightly colored, orange larvae that can be found eating aphids on the leaf surface. These predacious larvae are present from mid-June throughout the summer. There are 3-6 generations per year. In addition to aphids, they also feed on soft-bodied scales and mealybugs.

SYRPHID FLY LARVAE (Family Syrphidae)

The Family Syrphidae contains the "hover flies", so named because of the adults' flying behavior. They are brightly colored with yellow and black stripes, resembling bees. Syrphids overwinter as pupae in the soil. In the spring, the adults emerge, mate, and lay single, long whitish eggs on foliage or bark, from early spring through mid-summer, usually among aphid colonies. One female lays several eggs. After hatching, the larvae feed on aphids by piercing their bodies and sucking the fluids, leaving shriveled, blackened aphid cadavers. These predacious larvae are shaped cylindrically and taper toward the head. There are 5 to 7 generations per year. Syrphid larvae feed on aphids, and may also feed on scales and caterpillars.

LADYBIRD BEETLES (Family Coccinellidae)

- Stethorus punctum - This ladybird beetle is an important predator of European red mite in parts of the northeast, particularly Pennsylvania, and has been observed intermittently in the Hudson Valley of N.Y., and occasionally in western N.Y. Stethorus overwinters as an adult in the "litter" and ground cover under trees, or in nearby protected places. The adults are rounded, oval, uniformly shiny black, and are about 1.3 to 1.5 mm (1/16 in.) long. Eggs are laid mostly on the undersides of the leaf, near the primary veins, at a density of 1 to 10 per leaf. They are small and pale white, and about 0.3 to 0.4 mm (1/85 in.) long. Eggs turn black just prior to hatching. The larva is gray to blackish with numerous hairs, but becomes reddish as it matures, starting on the edges and completing the change just prior to pupation. There are 3 generations per year in south-central Pennsylvania, with peak periods of larval activity in mid-May, mid-June and mid-August. The pupa is uniformly black, small and flattened, and is attached to the leaf.

- Other Ladybird Beetles - Ladybird beetles are very efficient predators of aphids, scales and mites. Adults are generally hemisphere-shaped, and brightly colored or black, ranging in size from 0.8 to over 8 mm (0.03 to 0.3 in.). They overwinter in sheltered places and become active in the spring. Eggs are laid on the undersides of leaves, usually near aphid colonies, and are typically yellow, spindle-shaped, and stand on end. Females may lay hundreds of eggs. The larvae have well-developed legs and resemble miniature alligators, and are brightly colored, usually black with yellow. The pupal case can often be seen attached to a leaf or branch. There are usually 1 to 2 generations per year. One notable species that is evident now is Coccinella septempunctata, the sevenspotted lady beetle, often referred to as C-7. This insect, which is large and reddish-orange with seven distinct black spots, was intentionally released into N.Y. state beginning in 1977, and has become established as an efficient predator in most parts of the state.

LACEWINGS (Family Chrysopidae)

Adult lacewings are green or brown insects with net-like, delicate wings, long antennae, and prominent eyes. The larvae are narrowly oval with two sickle-shaped mouthparts, which are used to pierce the prey and extract fluids. Often the larvae are covered with "trash", which is actually the bodies of their prey and other debris. Lacewings overwinter as larvae in cocoons, inside bark cracks or in leaves on the ground. In the spring, adults become active and lay eggs on the trunks and branches. These whitish eggs are laid singly and can be seen connected to the leaf by a long, threadlike "stem". Lacewings feed on aphids, leafhoppers, scales, mites, and eggs of Lepidoptera (butterflies and moths).

TRUE BUGS (Order Hemiptera)

There are many species of "true bugs" (Order Hemiptera) such as tarnished plant bug, that feed on plants, but a number of them are also predators of pest species. The ones most likely to be seen are "assassin bugs" or reduviids (Family Reduviidae), and "damsel bugs" or nabids (Family Nabidae). These types of predators typically have front legs that are efficient at grasping and holding their prey.

PARASITOIDS

Parasitoids are insects that feed on or in the tissue of other insects, consuming all or most of their host and eventually killing it. They are typically small wasps (Order Hymenoptera), or flies (Order Diptera). Although the adult flies or wasps may be seen occasionally in an orchard, it is much more common to observe the eggs, larvae, or pupae in or on the parasitized pest insect. Eggs may be laid directly on a host such as the obliquebanded leafroller, or near the host, such as in the mine of a spotted tentiform leafminer. After the parasitoid consumes the pest, it is not unusual to find the parasitized larvae or eggs of a moth host, or aphids that have been parastized ("mummies"). Exit holes can be seen where the parasitoid adult has emerged from the aphid mummy.

SPOTTED TENTIFORM LEAFMINER

by:Harvey Reissig & Art Agnello, Entomology, Geneva The injury caused by the second and third generations is identical to that caused by the first, but second-generation injury is most damaging to the tree. Third-generation STLM is usually not a problem if the second generation was controlled properly. Proper timing is essential for both the assessment of STLM densities and control, if required. If done too early, sampling will underestimate the population. If control is applied too late, it will not be effective. Sampling for sap-feeding mines should be done at approximately 690 degree-days (base 43 F) after the start of the flight of the second generation. The second-generation flight began last week in the Hudson Valley, and it appears to be starting in Geneva today, although slowly. If moth trap data or DD readings are not available in your area, July 9 is a rough approximation of the appropriate sampling time. Although this procedure may require as many as three separate sampling sessions to properly determine the need for a treatment, the total time spent sampling a given block should not exceed 30 minutes. A decision regarding the third generation is generally not required unless the density of the second brood exceeded two mines per leaf. In recent years, approximately 8% of sampled orchards have required a treatment for second-generation STLM.

Several insecticides are effective against second-generation STLM, including Vydate, Lannate, Asana, and Provado. All of these products except for Provado are highly detrimental to predatory mites. Depending on the product chosen, application can be made anytime from initial egg deposition until larvae enter the tissue-feeding stages. Sampling is, of course, recommended before any spray is applied. If Provado is chosen, the manufacturer recommends aiming for the period 10-14 days after the flight starts. Unfortunately, if mines haven't yet begun to show up, this approach requires you to predict the need for a treatment based on either moth numbers or past field history, neither of which has been shown to be a reliable indicator of actual pressure. According to our experience with this material, waiting until the appearance of early sap-feeding mines will give a better picture of problem blocks, and should still be timely enough to effectively manage economic populations. Regardless of when an application is made, we don't know ahead of time whether another spray will be needed, but considering the aphid and leafhopper potential in our region under the current hot and dry conditions, a second application might eventually end up being elected anyway.








We have heard from Uniroyal Chemical Co. that a Special Local Need label has been issued by the N.Y.S. DEC for Omite 6E against mites on apples, so this formulation is once again available for use in N.Y. in addition to the 30WP. Recall that the WP formulation is restricted to 3 applications per year (7-day PHI), and the EC formulaiton to 2 per year (14-day PHI). If alternating between formulations, do not exceed 10.8 lb a.i./acre per season.

ERRATA

OFF-BASE

The May 30 article on Harvey Reissig's OBLR research last year incorrectly stated that his degree-day timings were based on 50 F. As with our sampling guidelines, the actual base is 43 F.

NO PLACE LIKE HOME PAGE

For those web-surfers out there who may have given up on seeing Scaffolds on the World Wide Web, we're relieved to announce that this publication is now on-line. However, it resides at a different URL from that previously advertised: http://www.nysaes.cornell.edu/ent/scaffolds/ (Yes, we know that "scaffolds" is misspelled in the address, but you'll just have to accept that as one of the programmer's mysteries). Actually, only the 1995 issues are located here, and not all of them (yet), but we're making progress on that front, and soon we should be up-to-date on this season's issues at least. Although we haven't yet installed all the hot-links we'd like to see, one nice feature is a keyword search capacity that shows you all occurrences of that word in the entire list of issues, along with active links to each occurrence in its context.

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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