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March 19, 2007 Volume 16 No. 1
Update on Pest Management and Crop Development |
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Upcoming Pest Events | Phenologies | General Info | Chem News | Insects | Diseases
Upcoming Pest Events | Phenologies | General Info | Chem News | Insects | Diseases Phenologies (Geneva): All dormant
Upcoming Pest Events | Phenologies | General Info | Chem News | Insects | Diseases
For the first time, the vernal equinox this year occurs after the daylight savings time change (a process that strikes me as akin to the belief that you can make a blanket longer by cutting 12 inches off one end and sewing it onto the other), so it will be harder than normal to be convinced of spring's arrival when the alarm goes off on Wednesday morning. For that matter, winter started so late this year, I'm not convinced it will actually give up without an extra month of NY-flavored seasoning, just to preserve some higher level of symmetry. What I can be sure of is that, even if that were to happen, the Law of Weather Conservation will see to it that at some inconvenient spot along the line, we'd be in for a horrific turbo-warmup to bring us approximately back to normal (or as close as we ever get to it). Which is all just a long way of stating, as I do each year, that this first issue of the year is as good a signal as any that I believe everything's happening right on schedule. You never call, you never write This year marks a bittersweet milestone of sorts, because, as I've been intimating for a few years, from now on, due to rising costs associated with sending out printed copies, we have been forced to go to an all-electronic format beginning this year. This was bound to happen eventually, given the diminishing number of print subscribers we had -- just 15 of our 265 total known subscribers had been receiving the hard copy only. We're sorry that we will be unable to continue sending it as a hard copy, but it was largely a question of economics. (Just think of it as our attempt to become more carbon-neutral.) Instead, We will be sending Scaffolds out as a pdf file via email each Tuesday morning. Naturally, there is also a web version available from the NYSAES server, which is normally up by Tuesday or Wednesday each week, at: http://www.nysaes.cornell.edu/ent/scaffolds As always, we are happy to consider contributions
(particularly from N.Y. sources) in the form of articles on topics
in any of the fruit crop protection or crop production areas, as
well as N.Y. field observations, trap data, etc.
Upcoming Pest Events | Phenologies | General Info | Chem News | Insects | Diseases
Label Changes • I noted this last year, but the new Imidan
label (released in January 2006) didn't actually hit the main distribution
points until summer. The new Imidan 70WP label changes are
mainly in the REI (re-entry interval) and seasonal limits for some
crops. All PHIs (pre-harvest intervals) remain the same. The
REIs for tree fruit crops went from 24 hours to 3 days.
Upcoming Pest Events | Phenologies | General Info | Chem News | Insects | Diseases
Recent reports in the news have highlighted a dramatic loss of honey bee colonies in as many as 24 states. Honey bees are a critical player in the production of many fruit, vegetable and seed crops grown throughout the country; and substantial colony losses, such as are currently being experienced, pose a real threat to growers who rely on bees for pollination. It is not clear whether the current problem, dubbed 'Colony Collapse Disorder' by some, is a new problem, or the result of existing problems that have beleaguered both bees and beekeepers for a number of years. The big problem has been parasitic mites. These mites transmit viruses and cause substantial colony losses each year. These losses reached catastrophic proportions during the winters of 1995-96 and 2000-01, when colony deaths approaching 80% in the northern states were observed. Unfortunately, effective and sustainable controls have not yet been developed for these mites, despite considerable efforts at both state and federal levels. Pesticide resistance is a major problem that contributes to period catastrophic losses on the scale currently being seen. While the symptoms associated with the current losses are similar to those previously seen with parasitic mites, several groups, including beekeepers, state regulatory agents and scientists from USDA-ARS and university labs, are investigating to determine if some other cause, such as a new pathogen or possible pesticide poisoning, is involved. Whatever the outcome, losses on this scale highlight the fragility of the commercial pollination system and the need to address the needs of the beekeeping industry in order to ensure a continued supply of healthy and affordable foods. Growers should assume that a there will be a shortage of colonies for pollination and higher rental fees this spring. Booking colonies as soon as possible is strongly recommended. Background Beekeeping has suffered several major setbacks during the last two decades. First, invasive parasitic mites have decimated honey bee populations throughout the US, creating instability in the supply of bees rented for pollination and greatly increasing the cost of managing bees and renting hives for pollination. The development of pesticide resistance in the mite population has exacerbated this problem. Second, the major bacterial disease affecting honey bees, American foulbrood, has developed resistance to the antibiotic used to prevent it. Although an alternative compound is now available, it is only a matter of time until resistance develops again. Third, cheap, imported honey has maintained strong downward pressure on the prices paid to US honey producers. Combined with increased production cost attributable to mites and disease, this has contributed to a reduction in the number of beekeepers and colonies. Finally, the Africanized honey bee has begun to move into regions of the country critical to the sustainability of the US beekeeping industry. These areas, primarily in the southeastern US, are the major wintering grounds for migratory beekeepers and the major source of queen and package bees purchased by northern beekeepers to replace winter losses, which are high. Africanized bees out-compete our traditional European bees in these areas, and as germplasm from this highly defensive race of bees become predominant in the commercial population, colonies will become less manageable. A weakened beekeeping industry affects not only beekeepers, but also fruit and vegetable growers, and the consumer; and the combined effect of these difficulties contributes to social stress in rural America and increase our dependence on foreign sources of food.
Upcoming Pest Events | Phenologies | General Info | Chem News | Insects | Diseases
Producing apples organically in northeastern United States is a challenging enterprise that requires great skill and attention to detail. Sulfur, liquid lime-sulfur (LLS), and copper fungicides are the only effective fungicides currently registered for disease control in organic orchards, and these fungicides all have significant limitations compared with most of the conventional fungicides used today. Other products registered for organic disease control on apples have so far proven both less effective and more expensive than sulfur in our eastern climate, where frequent rain events compromise the effectiveness of biocontrols and biorational products. Copper and sulfur have no curative activity. In that respect, they have the same limitations as captan and mancozeb fungicides. However, copper applied between half-inch green and bloom can cause fruit russetting (Fig. 1), and copper applied between petal fall and early July can cause blackened lenticels on fruit (Fig. 2).
Low rates of copper can be used to control summer diseases from mid-July through September, but only a few formulations are labeled for use during summer. Yellow-skinned apples are more prone to skin discoloration from summer copper sprays than red-skinned apples. Copper fungicides are being phased out of organic production in Europe, and the future for copper in organic production in the United States is questionable. So long as copper fungicides remain acceptable, they should be used in organic orchards in the first one or two sprays each season to help suppress fire blight and again in late summer sprays to help control summer diseases and fruit rots. Sulfur is a good protectant, but it is prone to wash-off during rains. Under most conditions, protection from sulfur will be compromised by an inch of rainfall, and it must therefore be applied frequently in wet seasons. The need for frequent re-applications during long rainy periods is one of the reasons that old-timers sometimes applied sulfur as a dust instead of as a spray. Dusting sulfur adhered well to wet leaves and orchards could be covered more quickly between rains with dusters than with sprayers. The best description I have seen for optimizing uses of wettable sulfur, dusting sulfur, and LLS for scab control was published by Burrell (1945). LLS is more effective than wettable sulfur for controlling apple scab and flyspeck, but LLS also causes more fruit russetting and depresses yield. Two percent LLS provides 48–72 hr of post-infection activity, depending on temperature. If scab lesions begin appearing on leaves, LLS can be applied to suppress sporulation and "burn out" lesions. In handgun trials at the Hudson Valley Lab, LLS provided good control of sooty blotch and flyspeck when applied on a 10-day schedule at 1 qt/100 gal of dilute spray. However a rate of 2qt/100 gal was required to control sooty blotch and flyspeck when sprays were applied on an 18–20 day interval. LLS at 2.5% is also an effective fruit thinner when applied with oil at petal fall and again 5–7 days later. The yield-depressing effects of sulfur and lime-sulfur sprays are well documented and have major economic implications for organic production systems that require repeated use of these fungicides. Palmiter and Smock (1954) published results of a 5-year study with McIntosh trees subjected to different spray regimes and showed that trees receiving ferbam fungicide sprays throughout the growing season produced 17% more harvestable fruit (based on boxes/tree) than did similar trees that received sulfur sprays. The yield of fruit that met U.S. No. 1 grade standards was 33% higher for ferbam-treated trees than for sulfur-treated trees. More recently, Holb et al. (2003) ran a two-year trial with Jonagold and Boskoop apples in Holland and found that yields in plots receiving conventional fungicides were 33 and 39% higher, respectively, than yields in comparable plots receiving full-season treatments of wettable sulfur or LLS. In addition to the yield loss, the latter two treatments also reduced the percentage of top-grade fruit by 10–15% compared with conventional fungicides. In a non-replicated trial that we conducted at the Hudson Valley Lab last summer, an organic spray program consisting mostly of sulfur, LLS, and Surround (for insect control) reduced yield of 15 cultivars in our test planting by an average of about 50% compared with comparable trees receiving standard fungicides. In all of these tests, yield differences were attributable solely to fungicide effects because all plots received the same fertilizer and herbicide regimes. Because of the tremendous yield-suppressing effects
of sulfur and LLS, organic apple production is likely to be most
successful in orchards that are designed and planted with organic
production in mind. Attempts to transition old unprofitable
blocks of scab-susceptible varieties into organic production "because
the apple will be worth more" is an almost certain recipe
for disaster. Instead, organic producers should design new
orchards with the following issues in mind: The following generalized rules may prove useful
for managing apple diseases in orchards where sulfur and LLS must
be used for scab control and where summer sprays are needed to
control flyspeck, sooty blotch, and summer fruit rots: Considerable research effort is being directed toward organic apple production at various universities. I have no doubt that we now have both the tools required for producing apples organically in the Northeast. However, I'm not yet convinced that anyone can make a profit growing organic apples in our climate due to the yield suppressive effects of sulfur and lime-sulfur and the high costs for pesticides required for insect control. Literature cited: Burrell, A. B. 1945. Practical use of our newer knowledge of apple
scab control. Proc. 90th Ann. Mtg. N.Y. St. Hortic. Soc. 90:9-16.
This material is based upon work supported by Smith Lever funds from the Cooperative State Research, Education, and Extension Service, U.S. Department of Agriculture. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture. 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 Online at <http://www.nysaes.cornell.edu/ent/scaffolds/> Return to top
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Last
October, after 4 years of work, we published a new reference that
should be of interest to growers, consultants, biologists, extensionists,
students, and home fruit growers. The Tree Fruit Field Guide
to Insect, Mite, and Disease Pests and Natural Enemies of Eastern
North America (Agnello, Chouinard, Firlej, Turechek, Vanoosthuyse,
and Vincent) is a 238-page handbook of fact sheet-type entries,
including color photos, descriptions and actual-size drawings,
distribution, damage symptoms and general management recommendations,
to help growers identify pest insects, mites, and diseases that
cause damage in the orchard, as well as beneficial insects, spiders,
and mites that can be found in tree fruit plantings. It includes
over 25 pages of diagnostic keys to insect and mite damage and
disease symptoms, a glossary and an index/cross-reference to common,
scientific, and family names; also, a list of recommended sources
for further information, including useful Internet sites. The
book is available through NRAES (Natural Resource, Agricultural,
and Engineering Service) in Ithaca, through its website: 
