Volume 7, No. 18                                                July 20, 1998

COMING EVENTS

                                                     43°F       50°F
Current DD accumulations (Geneva 1/1-7/20):         2146      1431     
                    (Geneva 1997 1/1-7/20):         1735      1128     
                (Geneva "Normal" 1/1-7/20):         1850      1315     
                       (Highland 1/1-7/20):         2421      1631     

Coming Events:                              Ranges:
Obliquebanded leafroller 2nd flight begins      2124-3040  1412-2076
Comstock mealybug 2nd gen. crawlers emerge      2106-2768  1447-1924
Apple maggot flight peak                        2033-2688  1387-1804
American plum borer 2nd flight peaks            1648-2612  1037-1840
Spotted tentiform leafminer 2nd flight subsides 1773-2514  1148-1818
Redbanded leafroller 2nd flight subsides        1927-3045  1291-2160
San Jose scale 2nd flight peaks                 1934-2591  1271-1874

PEST FOCUS
   Geneva: Timing of control spray for 2nd brood Codling Moth = 1260 DD 
              (base 50°F) after biofix date (5/7). DD since then = 1190.
  
 Highland: Timing of control spray for 2nd brood Codling Moth = 1260 DD 
              (base 50°F) after biofix date (5/4). DD since then = 1324.


TRAP CATCHES (Number/trap/day)
Geneva:     
                                   7/6   7/10   7/13   7/16   7/20
Spotted Tentiform Leafminer        385    314     52     51     13
Redbanded Leafroller               2.0    1.7    0.8    1.3    0.5
Oriental Fruit Moth (apple)        1.5    0.8    1.8    0.6    1.0
Lesser Appleworm                   1.3    0.5    3.0    0.5    0.3
Codling Moth                       1.6    7.5    2.7    2.6    5.0
San Jose Scale                     1.0    1.3    0.3    2.0    4.8
American Plum Borer                2.6    1.0    1.8    1.4    1.7
Lesser Peachtree Borer             1.6    0.5    1.8    0.5    0.8
Peachtree Borer                    2.3    0.7    0.3    0.9    1.0
Pandemis Leafroller                  0      0      0      0      0
Obliquebanded Leafroller             0      0      0      0      0
Apple Maggot                       0.1      0      0    0.1      0

Highland (Dick Straub, Peter Jentsch):
                                  6/22   6/29    7/7   7/13   7/20
Spotted Tentiform Leafminer       23.5   40.1   43.0   13.6   26.9
Redbanded Leafroller               0.3    2.4    2.4    1.0    1.7
Oriental Fruit Moth                0.1    0.4      0    0.2    0.1
Lesser Appleworm                     0      0    0.3    0.1    0.4
Codling Moth                       1.4    1.6    0.4    0.5    2.3
Obliquebanded Leafroller             0      0    0.1    0.1      0
Variegated Leafroller              0.2    1.1    0.6    0.1      0
Tufted apple budmoth               0.9    1.8    3.6    1.9    0.3
Fruittree Leafroller               0.1    0.1      0      0      0
Sparganothis Fruitworm             0.9*   0.7    0.8      0      0
Apple Maggot                       0.1*   0.1    0.1   0.14    0.2
                                                            * 1st catch

Green Movement

Joe Kovach,
IPM, Geneva

Naturally occuring pesticides that are derived from plants or plant parts are commonly referred to as "botanicals". Botanicals have been around for quite a while. Along with arsenicals and other inorganic pesticides, they were pretty commonly used before the advent of the synthetic, organic pesticides rendered them "obsolete". From time to time they're re-examined for various reasons and may be familiar. Botanicals are of interest to those concerned with pest management for a variety of reasons. They are generally less toxic to the applicator than many synthetic pesticides. They may be acceptable in the organic market where synthetic pesticides are not. Because, in general, they break down quickly, they may also be of use near harvest, when control is needed but other materials may not be applied because of PHI restrictions. Rapid degradation also means they are less likely to become environmental problems. Botanicals, however, are not without concerns. They are usually broad spectrum poisons that can be hard on beneficial insects. And, unlike "biological" pesticides like B.t.'s, insect growth regulators and pheromones, they are somewhat acutely toxic to humans and other mammals. The fact that they break down rapidly in the environment, while an advantage in some respects, also means that sprays need to be:

• timed precisely to coincide with pest events,
• applied at lower thresholds and, possibly,
• applied more often.
• They are also very expensive.

The four most common botanicals available for use in fruit crops today are rotenone, pyrethrin, sabadilla and ryania. Information on these products appears in the 1998 Tree-Fruit Recommendations (pp. 20­21). A relatively newer, and increasingly more common botanical insecticide that is receiving a lot of attention these days is azadirachtin (or neem).

ROTENONE
Rotenone is derived from the root of various plants of the Derris or Lonchocarpus species from Southeast Asia, Central and South America. It is available as at least 118 formulated products from a large number of manufacturers. It is synergized by the addition of piperonyl butoxide (PBO), which is another botanical material. Rotenone is expensive compared with synthetic insecticides, but is moderately priced for a botanical. It is the most commonly mentioned of the botanicals in pre-synthetic literature and is at least somewhat effective against a large number of insect pests. These include: pear psylla, strawberry leafroller, European corn borer, European apple sawfly, cherry fruit fly, apple maggot, cranberry fruitworm, raspberry fruitworm, pea aphid (which is similar to rosy apple aphid), European red mite and two-spotted spider mite, codling moth, plum curculio, Japanese beetle and tarnished plant bug. Unfortunately, it is also toxic to ladybird beetles and predatory mites. But, it is non-toxic to syrphid flies that feed on aphids, and to honeybees. Rotenone is rapidly degraded by sunlight, lasting a week or less.

Of the botanicals mentioned here, rotenone is the most toxic to humans and other mammals. The acute oral LD50 is from 60­1500 mg/kg. In small doses it may be irritating or numbing to mucous membranes. It is highly toxic to fish, having been commonly used as a fish poison. It is also toxic to birds and pigs.

PYTRETHRIN
(Pyrethrum)
This compound is produced in the flowers of Chrysanthemum cinerariaefolium and is the forerunner of the synthetic pyrethroid insecticides. There are not nearly as many commercially available formulations of this chemical as there are for rotenone, but it is available as an emulsifiable concentrate, in combination with rotenone, or alone as a wettable powder, from at least a couple of sources. Pyrethrin is the least expensive of these four materials. Depending on the rate used, it may be less expensive than many synthetic insecticides. It is also synergized by PBO. Pyrethrin is labelled against a large number of pests. An addendum to the label for one formulation of pyrethrin showed it to be moderately to highly effective (61­100% control) against the following pests of fruit: grape leafhopper, potato leafhopper, leaf curl plum aphid, blueberry flea beetle, blueberry thrips and blueberry sawfly. It is also effective against cranberry fruitworm. It is quickly broken down in the environment and may be used up to and including the day of harvest.

Pyrethrin is relatively non-toxic to humans and other mammals, although the dust produces allergy attacks in people who are allergic to ragweed pollen. The acute oral LD50 is 1200­1500 mg/kg. It is toxic to fish, but "relatively" non-toxic to honey bees.

Pyrethrum Daisy

Sabadilla is less toxic to mammals than rotenone or pyrethrin; the acute oral LD50 is greater than 4000 mg/kg.

RYANIA
Rumor had it last season that the registration of ryanodine, the active ingredient in Ryania insecticides, would be voluntarily cancelled by the manufacturers of these products. Our most current searches yielded no active registrations for the use of ryanodine; all uses have indeed been cancelled. However, we are informed by Dunhill Chemical, manufacturers of Ryan 50, that because cancellation was voluntary, existing stocks of ryanodine products may used by growers, and sold by distributors, until they are used up. Therefore, we will once again present pertinent information about ryania in this article:

A product of the roots and stems of Ryania speciosa of Trinidad, ryania acts as both a stomach and contact poison on target insects. It is the most expensive of the materials covered in this article. Ryanodine, the active ingredient, is formulated as a wettable powder and is labelled for use against the codling moth in apples. It is also toxic to the European corn borer and may control cranberry fruitworm. In Joe Kovach's tests it provided excellent control of a pest complex comprising codling moth, oriental fruit moth and lesser appleworm. It also controlled aphids, white apple leafhopper and spotted tentiform leafminer. It is more persistent than rotenone or pyrethrin and is more selective. It is generally not very harmful to pest predators and parasites, but is somewhat toxic to the predators Atractotomus mali and Diaphnocoris spp. It may also be used up to 24 hours before harvest.

The acute oral LD50 of ryania is 750­1200 mg/kg, less toxic than rotenone and slightly more toxic than pyrethrin. It is also toxic to fish.

Neem Fruit

The most common commercial formulations of neem available for N.Y. tree fruit is Neemix (W. R. Grace & Co.), which lists leafminers, mealybugs, aphids, fruit flies, caterpillars and psylla, and Align (AgriDyne), which includes some minor leafrollers on the label. Azadirachtin has shown good activity against spotted tentiform leafminer in tests in past years, but the formulation that was available at that time was somewhat phytotoxic. In Dick Straub's insecticide trials in 1992 with another azadirachtin product called Margosan-O, the insecticide showed good activity against STLM and leafhopper. Margosan-O is no longer available for fruit crops. In laboratory tests by Jan Nyrop's lab, toxicity to the predatory mite Amblyseius fallacis was very low. Field trials against OBLR by Harvey Reissig last year were not encouraging.

Azadirachtin is relatively short-lived and mammalian toxicity is low (rat oral LD50 >10,000). It can be used up to and including the day of harvest and reentry is permitted without protective clothing after the spray has dried. It is toxic to fish and aquatic invertebrates.

PIPERONYL BUTOXIDE (PBO)
PBO is a synergist (in this case, a material that when added to a pesticide increases the activity of its active ingredient) of both rotenone and pyrethrin. It is also a botanical product, being derived from Brazilian sassafras. Acutely, it is very safe, having an acute oral LD50 of greater than 7,500 mg/kg, but it may be chronically toxic in high doses.

GARLIC (Guardian)
A 10% formulation of garlic is registered on apples and a number of apple pests are on the label. In 1995, Guardian (supplied by THUMBS-UP Sales Co., Chesterland, OH) was applied in six sprays at two-week intervals, starting at petal fall, and compared with a 3-spray Imidan program. Following the manufacturer's recommendations, each application of Guardian included an adjuvant of Sylgard 309 and Tri-Fol, a buffering agent, to maintain an optimum pH below 5.5­6.0. Results showed that the garlic spray applied at a rate of 11 oz/A did not provide control of any of the labelled apple arthropod pests in N.Y. and did not affect the population density of two predator species commonly found in apples. The foliar pests ‹ aphids, leafminers and mite populations ‹ were unaffected by the garlic sprays. The fruit pests ‹ plum curculio, tarnished plant bug, obliquebanded leafroller and internal lepidopterans ‹ were also not affected by the biweekly sprays. However, the garlic did not have any effect on the population density of the predators T. pyri or Aphidoletes aphidimyza.


BIBLIOGRAPHY

Allen, T.C.  1945.  A compilation of recent insecticidal tests of 
  Sabadilla, Schoenocaulon spp.  Dept. of Economic Entomology, Univ. of 
  Wisconsin, Madison Wisconsin.  NOT RELEASED FOR PUBLICATION

Brown, A.W.A.  1951.  Insect Control by Chemicals.  Wiley & Sons, Inc. 
  New York. 

Garman, P.  1943.  Control of the apple maggot with rotenone dusts.  
  Bulletin of the Connecticut Agricultural Experiment Station.  Bull. 
  474  pp. 435-442.

Hardman, J.M., H.J. Herbert, K.H. Sanford and D. Hamilton.  1985.  
  Effect of populations of the European red mite, Panonychus ulmi, on 
  the apple variety Red Delicious in Nova Scotia.  Can. Entomol. 117: 
  1257-1265. 

Hofstetter, B.  1991.  Before you buy botanical pest controls ...  The 
  New Farm.  Dec. 1991.  pp. 36-39.

Kovach, J., H. Reissig and J. Nyrop.  1990.  Effect of botanical 
  insecticides on the New York apple pest complex.  Reports from the 
  1989 IPM Research, Development and Implementation Projects in Fruit.  
  New York State IPM Program, Cornell Univ. and NYS Dept. of Ag. and 
  Markets.  IPM Publication #202. pp. 40-44.

Morse, J.G. and T.S. Bellows, Jr.  1986.  Toxicity of major citrus 
  pesticides to Aphytis melinus (Hymenoptera: Aphelinidae) and 
  Cryptolaemus montrouzieri (Coleoptera: Coccinellidae).  J. Econ. 
  Entomol. 79: 311-314. 

Morse, J.G., H.S. Elmer,  O.L. Brawner.  1986.  Resistant thrips:  The 
  1986 control recommendations for California.  Citrograph, the magazine 
  of the citrus industry. Riverside, CA  71(6): 118-120.

Morse, J.G., J.A. Immaraju,  O.L. Brawner.  1988.  Citrus thrips: 
  Looking to the future.  Citrograph, the magazine of the citrus 
  industry. Riverside, CA  73(6): 112-115.

Strickler, K. and B.A. Croft.  1985.  Comparative rotenone toxicity in 
  the predator, Amblyseius fallacis (Acari: Phytoseidae), and the 
  herbivore, Tetranychus urticae (Acari: Tetranychidae), grown on lima beans and cucumbers.  
  Environ. Entomol. 14: 243-246.

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 (5/7 in Geneva, 5/4 in the Hudson Valley). As of today, 7/20, 1190 DD have accumulated in Geneva and 1324 at Highland, which means that any needed sprays should be under way in both western N.Y. and the Hudson Valley. In cases of severe population pressure, a spray of an OP material now can be backed up by a second application against the same brood 14 days later.

FIELD DAY ANNOUNCEMENT

It's not too early to mark your calendar for the annual N.Y. Fruit Pest Control Field Day, which will take place during Labor Day week on Sept. 9 and 10, as dictated by tradition. However, in contrast to our traditional practice (for complicated reasons of scheduling), the Hudson Valley component will take place on the later date this year. Activities will commence in Geneva on Wednesday, the 9th, with registration, coffee, donuts, and cider at Barton Laboratory, 8:30 am. We will then view and discuss results from field trials on tree fruits and grapes. It is anticipated that the tour of field plots will be completed by noon or early afternoon. On Thursday, the 10th, Highland participants will register starting at 8:30 in the recently commemorated Hudson Valley Lab, after which they will proceed to the orchards to view plots and preliminary data from field trials involving new fungicides, miticides, and insecticides on apples and grapes. Save the dates.

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: ama4@cornell.edu

NOTE: Every effort has been made to provide correct, complete and up-to-date pesticide recommendations. Nevertheless, changes in pesticide regulations occur constantly, and human errors are possible. These recommendations are not a substitute for pesticide labelling. Please read the label before applying any pesticide.

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Photographs courtesy of New York State Integrated Pest Management Program