MASSACHUSETTS BERRY NOTES

Summer Edition 2001 #10

Vol. 13, No. 15

August 9, 2001

http://www.umass.edu/fruitadvisor/berrynotes/index.html

Volume 13-- 2001

Berry Notes is compiled and edited by Sonia Schloemann. Authors and sources are cited for all articles. Publication is funded in part by the UMass Extension Agroecology Program and grower subscriptions. A text version can be e-mailed to you if you contact Sonia Schloemann at 413-545-4347, sgs@umext.umass.edu. Please cite the original source if reprinting information.

Please Note: This is the last issue of the weekly summer series. The next issue of Berry Notes will resume the monthly schedule and will come out in late August.

Crop Conditions and Pest Summary

Tissue testing is a procedure by which one can determine the nutritional status of a plant by testing the plant tissues. This, in combination with regular soil tests, can help to fine tune fertilizer applications so that plants are receiving the nutrition needed to produce optimal crops. Now is a good time to sample tissue for testing. Enclosed with this mailing is a copy of the submission form (PDF or Word Document) used by the UMass Soil and Tissue Testing Lab. Instructions for collecting tissue samples are included in the form. Please call me if you have any questions. Strawberry fields are fairly quiet at this time of year. But, irrigation is still very important at this time of year to ensure good crown expansion, runner production and flower bud initiation for next year. Anyone who is growing dayneutral strawberries, especially ‘Seascape’, I'd like to hear how your season is going. Give me a call. Highbush blueberry harvest is moving into the late season. Hot weather is accelerating fruit ripening. Some growers report high levels of anthracnose in the late varieties. Yield is variable around the state, but overall seems to be down from recent years. Blueberry maggot fly levels have been lower than recent years, too. Following the discovery of the Blueberry Scorch virus in New England, growers should be sure to check their bushes for the presence of aphids. Controlling aphids is the key to preventing the spread of this virus to healthy bushes. Wild blueberry harvest is also progressing quite well. So well, in fact, that one veteran picker at a Heath wild blueberry farm, picked his personal best and farm record of 110 20# boxes, over a ton of blueberries, in one day this week! (A hot one at that.) Way to go! Summer raspberry harvest is winding down especially with this hot weather. Floricane removal should wait until the winter, unless spur or cane blight are a problem. Black raspberry and blackberry primocanes should be tipped now to encourage lateral growth. Pinch off tips at a height about 6-8 inches above the height of your top trellis wire. Mites (both two-spotted spider mites and European red mites) are flaring up in some locations. Predator releases will help suppress them without the need for sprays during harvest. Call me for sources (413-545-4347). Fall raspberries will be ripening soon. Make sure that you have the support trellis installed to prevent lodging of the canes as the fruit sizes up and gets heavier. Grapes veraison (berry coloring) is beginning now. See more about this in the Grape section. Dry conditions in the vineyards are causing some drought stress, especially on young vines. Since no appreciable rain is predicted for the coming week, supplemental irrigation may be needed on lighter soils.

We would all like to forget the weather of 2000. Extremely wet soil conditions prevailed during and after harvest. Unfortunately, for perennial crops like strawberries, the effects of last years' weather will remain with us for a few years. Take a good look at your soil conditions and be aware of any compaction problems what may be affecting crop health.

Symptoms of soil compaction:

· Standing water, poor drainage

· Early moisture stress when weather turns dry

· More root diseases, more nutrient deficiency symptoms

· Stunted unthrifty plants, with poor winter survival

Assessing the problem:

Use a tile probe to check the field for areas of compaction. Push the probe slowly and steadily into the soil, feeling for layers of resistance. Probe an area in the fence-row for comparison. If the soil is compacted, you may notice differences within the rows compared to between the rows. This test does not work well in very dry soil, because as soil dries out, soil strength increases.

A small pit can be dug across the row to examine crop roots. Use a knife to pick away the soil and expose the root system. Roots growing in compacted soil are generally smaller and tend to grow sideways instead of down.

What to do about compaction:

· Fall and winter freeze thaw cycles will alleviate a small amount of compaction

· Use best management practices to prevent soil compaction: stay off the field when soil is wet

· Sub-soil to break up compacted layers of soil

Do not subsoil when soil is wet. To maximize shattering action and prevent further compaction, soil should be quite dry. Check the soil moisture at the lowest depth that the subsoil tool will be running. (Source: The All Ontario Berry Grower, Volume #00.8 - August/2001)

Some blueberry growers are using Neem-based insecticides, such as Ecozin, Neemix and Aza-Direct, to repel Japanese beetles out of bushes before harvest. Recent trials at the Trevor Nichols Research Complex showed that when the product Aza-Direct is sprayed on ripe berries, it appears to remove the waxy "bloom" on berries. Although this doesn't appear to have any negative physiological effects on the plant itself, the mottled look on the fruit could be a concern for fresh market growers. When viewed five days after the spray (and after a heavy rainfall), the "bloom" again appeared normal on the Aza-Direct treated fruit. This suggests that the waxy covering was not actually removed from the berry but only temporarily discolored. Caution is advised. (Source: Fruit Crop Advisory Team Alert, Vol. 16, No.15 , July 24, 2001)

Last month I noticed a number of primocanes that were wilting and dying in the blackberry plantings at the State Fruit Experiment Station. As the symptoms appeared after a windstorm, my first thought was that the canes were damaged by high winds. Upon examining many of the canes, however, it was evident that the damage was due in part to the activities of the raspberry crown borer.

The adult raspberry crown borer is a clearwing moth that resembles a hornet or yellowjacket. The mature larvae are 1 - 1.5 inches long, white, with a brown head. The adult moths emerge in late summer, mate, and lay numerous eggs on the underside of blackberry leaves. After hatching the larvae move to the base of the canes, form a blister-like hibernaculum at the base of the cane, and begin boring numerous galleries into the crown the following spring. The larvae continue to feed for two seasons. The larvae form pupae during midsummer of the second year, and adults emerge in late summer to complete the life cycle.

Damage caused by the raspberry crown borer is insidious and can be mistaken for the symptoms of several diseases. Above ground symptoms include loss of stand vigor and spindly canes. Individual canes may wilt or lodge, particularly after windy periods when the soil is moist. Crown injury is evident when affected canes are pulled up and examined. Roots and crowns may be girdled, and cavities bored into the interior of the crown. Check any primocanes that suddenly wilt or break at the crown for signs of infestation. The larvae may be noted by splitting infested canes.

Control of raspberry crown borer begins by removing alternate hosts, such as wild blackberries, from the vicinity of the planting. If practical, eliminate infested canes and crown from the planting. At present there are no insecticides specifically labeled for raspberry crown borer control in Missouri. A postharvest application of an insecticide labeled for other insect pests may give some control of emerging raspberry crown borer adults, particularly if the spray is directed to the base of the canes. Control of the raspberry crown borer may not be achieved until after 2-3 years of treatment. (Source: The Berry Basket, Vol. 4, No. 2, Summer 2001)

Signs of veraison, the beginning of the ripening period, are being seen. This is the period of rapid sugar accumulation in the fruit; a decrease in acidity occurs, primarily due to the respiration of malic acid; white grapes lose their grassy green color and may take on a more yellow or golden hue; red grapes start to develop color; and berries soften due to an influx of water. A key concept to remember is that most of the sugars and acids are produced in leaves and transported to the clusters. Therefore the maintenance of an adequate amount of healthy canopy is critical for proper ripening. An insufficient number of leaves or a canopy that has been ravaged by disease, insects or tractor operators may very well limit the ability of the vine to properly ripen its crop. (Source: Long Island Fruit & Vegetable Update, No. 22, Aug. 3, 2001)

It’s Here: The first Pinot Noir berries began to turn at the research vineyard on July 25. This is reminiscent of 1999, when the first signs of veraison were also noted on July 25. Interesting that early signs of veraison were seen on the same calendar date given that the two seasons are 150 GDD’s apart. One possibility is that, in 2001, more GDD’s have been accumulated during the day and/or nights have been cooler. One flaw with the GDD system is that accumulation continues during the nighttime hours when obviously there is no photosynthesis taking place.

Recall in the 1999 season that there was some Botrytis going into veraison. Some growers contained it, some did not. The tropical storm in mid-September 1999 did not help some of the riper Chardonnay blocks. Here, not only did Botrytis kick in big time but also after that storm, Chardonnay ripening hit a plateau and did not progress. Reds were not affected by the storm. In 2000, many blocks had Botrytis early. It did not progress due to a very dry fall. This season, so far, clusters are clean and hopefully we can dodge any deluges. (Source: Long Island Fruit & Vegetable Update, No. 21, July 27, 2001)

According to grape pathologist Wayne Wilcox and verified by local research, this is the single most important treatment for Botrytis. Susceptible varieties include Chardonnay, Riesling, Sauvignon Blanc, Gewurztraminer, Pinot Gris and Pinot Noir. Red varieties such as Merlot and Cabernet Sauvignon rarely develop cluster rot, though it has happened in very wet falls. Candidate materials are Vangard, Elevate and Rovral. The following is from Wilcox’s annual disease review.

Vangard is shaping up to be the "go to" Botrytis fungicide, but don’t overdo it. Remember that Vangard is highly prone to resistance development, and therefore is labeled for a maximum of two applications per season (one per season is better from a resistance-management standpoint). However, even if you apply "only" one or two Botrytis sprays per season, don’t use Vangard as the only Botrytis fungicide year after year. This is a good way to burn it out, and you will. Fortunately, we now have several unrelated products for Botrytis control, so it’s not hard to rotate compounds in a control program. Vangard is a systemic fungicide that penetrates berries and flowers (so it’s rainfast) but doesn’t move from berry to berry. It’s not related to any other product, and doesn’t control any disease except Botrytis [Ed.’s note: the label says that Vangard suppresses - not controls but suppresses - powdery mildew]. It’s been classified as a "reduced risk" compound by the EPA (good environmental and toxicology characteristics).

Last year was the first season for the commercial use of Elevate in NY, and it seemed to do a good job against Botrytis. Wilcox has generally gotten good results in his own control trials, although Vangard has been a little more consistent. The resistance risk for Elevate in still a bit unclear, but it appears to be "moderate". Elevate is not related to any other fungicide on the market, so can (and should) be used in rotational programs for resistance management purposes. Like Vangard, it’s been classified by the EPA as a "reduced risk" fungicide. It does not control any other grape diseases. Elevate is not systemic.

The third choice is Rovral. Rovral has been around 15+ years. Based on observations and the fact that Rovral did poorly in a local 1999 research trial, it is likely that long term use of Rovral has led to the development of resistance. Rovral resistance can be managed, however, by doing two things. First leave Rovral out of the schedule completely for at least one season. Then, if Botrytis treatments are needed, reintroduce Rovral but only in the rotational program described above.

Final comments on Botrytis ñ controlling vine vigor by moderating nitrogen and maintaining good air circulation through the canopy and the cluster zone are key elements of a Botrytis control program. Succulent growth and shaded canopies provide the perfect recipe for Botrytis. Questions have arisen in the past about the use of gibberellic acid (GA) for loosening up tight clustered varieties. The use of GA (in the springtime) on seeded winegrapes is a risky proposition at best and can lead to significant crop losses in both the current and subsequent seasons. (Source: Long Island Fruit & Vegetable Update, No. 21, July 27, 2001)

Is it cost effective to put up two-strand electric fence for deer control? Will it keep deer out? I recently talked with a grower in central Massachusetts whose pumpkins and squash have suffered serious deer damage in past years. For the second year he has installed electric fence in his fields and is very happy with the results. Recently he set up fence for a 4-acre field. Here are his costs:

$200 - solar charger

$30 - corner posts (5-foot T-post for strong corner support)

$30 -insulators

$70 -wire (17 guage wire)

$120 -rods for supporting fence. He buys 3/8 inch solid round metal rods and has them cut to length, $1 each. Spaced 25-30 feet apart.

Total materials cost: $450, or $112.50 per acre.

Total labor to install: 2 workers, half day.

He places the strands at 18-20 inches and 48 inches. He baits it right away with peanut butter in heavy aluminum foil squeezed onto the wire, about 12-14 baits for four acres, placed on the sides near the woods where deer would enter the field. He finds that baiting once is enough, since deer learn to avoid the fence once they contact it, and he gets fence up before they start feeding in a field. His experience with this fence: deer do not cross it.

All parts will be reused next year except the wire, which he discards because it is lightweight and tangles easily.

How many pumpkins (made unmarketable because of one deer bite) does it take to recoup the investment of less than $150 per acre? (Source: Vegetable IPM Newsletter August 2, 2001, Vol. 12, No. 12)

Nationally, several recent outbreaks of enteric illness associated with farm animals have highlighted the importance of safety whenever contact between animals and the public is permitted. The Massachusetts Department of Public Health (MDPH) has recently released "Recommendations for Petting Zoos, Petting Farms, Animal Fairs, and Other Events where Contact between Animals and the Public is Permitted". The purpose of these recommendations is to decrease human exposures to rabies and to other illnesses transmitted from animals to people.

Diseases that can be transmitted from animals to people are called zoonotic diseases. Zoonotic diseases include enteric, or diarrheal illnesses caused by organisms such as E. coli 0157:H7, salmonella and cryptosporidium. Rabies, catscratch disease and psittacosis are also examples of zoonotic diseases. Certain groups of people may be more susceptible to these illnesses. These groups include infants, children, pregnant women and those with a weakened immune system.

One of the most important measures to prevent the transmission of zoonotic diseases to people is providing adequate hand washing facilities anywhere contact between animals and the public is permitted. Additionally, eating and drinking in animal areas should not be allowed, and visitors to animals‚ events or farms should NEVER be allowed to sample animal feed or drink raw milk.

Animals should be closely monitored for signs of illness, and human contact with animals should always be supervised.

To view a complete copy of these new recommendations, go to the MDPH web site at www.state.ma.us/dph/ (Source: Massachusetts Department of Food & Agriculture: Farm & Market Report, Vol.78, No. 7, July 2001)

Questions & Answers:

Q: I'm noticing a bit of black rot in some vinifera clusters. Any organic solution? Picking each one out is not an option. St. Catharines, Ontario

A: At Maple Ridge (organic) we found that the prevention method is best, but we did have to go into panic mode two years ago. After talking with Dr. Poole and others at Cornell we decided on the following and it seems to be working:

PREVENTION

· Clean Vineyard floor after pruning (100% removal of dead vine parts)

· Keep plants healthy

· Seaweed spray frequently

· Fertilizer to maintain healthy plant parts

· Leaf removal around clusters

· Adjust soil to maintain balance recommended by Extension Service (i.e., lime to adjust acidity )

· Seasonal sprays of beneficial fungae (mycostop)

· Single fruiting zone to optimize canopy management

CONTROL (PANIC)

· Spray Oxidate - kills beneficials and bad stuff together, wears off in 1 hour, sterilizers whatever it touches

· Immediately follow up with lots of beneficial fungus (mycostop is good)

· Repeat Oxidate and mycostop if necessary

Only do this once, and then really turn on the PREVENTION program next season!

It is our experience that once the grapes hit 5 brix the damage scales back to almost zero. Black rot appears to become significantly less effective at 5 brix. Therefore, the Oxidate/mycostop panic program can be cancelled once 5 brix is achieved. (Source: Organic Viticulture Listserve, ORGANICVITICULTURE@yahoogroups.com)

Volume 13-- 2001

Crop Conditions and Pest Summary

Strawberry

Soil Compaction: Has it Happened to You? Anne Verhallen, OMAFRA

Highbush Blueberry

Use of Neem-based Products in Blueberry– John Wise, Michigan State University

Brambles

Raspberry Crown Borer Damage on Blackberries– Patrick Byers, Southern Missouri State Univ.

Grapes

Long Island Grape Update – Alice Wise, Cornell University

Veraison Botrytis Spray – Alice Wise, Wayne Wilcox Cornell University

General

Electric Fence For Deer: One Grower’s Cost Figures – Ruth Hazzard, UMass Extension

Cover Crops on the Web, Pam Fisher, OMAFRA

New Petting Farm/Zoo Recommendations

Questions & Answers:

Meetings

Field Grown Cut Flowers Video Teleconference

sponsored by the University of Massachusetts Extension Floriculture Program