June 1, 1999
Compiled by Vern Grubinger, University of Vermont Extension
(802) 257-7967 verng@sover.net

It's raining today but until now dry has been the word across the region. Are we in for another drought/flood/drought season. Let's hope not. Strawberry growers have been up late (early?) a lot last week irrigating for frost protection. Asparagus was frosted at many locations. In combination with the dry wind even peas and kale surprisingly showed frost injury. Potato aphids have been identified in greenhouse tomatoes. Growers are complaining that labor is tight, but bedding plant sales are reported strong. (Vern)

Dry, dry, dry. And the wind! We have our corn in and are ready to put in our winter and summer squash. Waiting for some rain if we can. Seen a few potato beetles in the greenhouse. Not much going on outside bugwise. Most everything seems like it is at a standstill just waiting for moisture now that the week of frosts has past. Our pond is down about 5 feet already. We keep hoping for some moderation. Even the flea beetles can't stand the weather. (Charlotte)

We expect a nice crop of strawberries (on both the annual bed and matted row systems) starting the end of next week; irrigation and row cover saved the blossoms last week from the multiple frosts. Asparagus has been harvested for about one week and turnips will be ready by the weekend. Peas are flowering and all crops moving ahead full speed with all the sun and continuous irrigation, including the weeds. Cultivating is on top priority and also working with little sleep due to lack of farm help. Just to be different, we are putting our 1956 Ford Fire truck with a Darley firepump back into service to pump irrigation water onto a new field down by a stream! Flea beetles still numerous and tarnish plant bugs appearing. (Argyle, NY)

With less than an inch of measurable rain since winter snowcover left conditions here are very dry with grass drying up and dying already along the edge of fields. Between four nights of frost last week and the constant winds hammering away and drying out transplants and seedings we have pumped more water this year already than we would in most total growing seasons. Work is slow for those of us with retail greenhouses,so we are behind in field work.Strawberrys should be in 10% bloom by 5/18 ,although plant size and foliage seems smaller than normal. No sign of clipper or measureable TPB, yet -better hold my tongue. (E. Hartland)

Dry windy conditions created a whirlwind that sent two giant pieces (15x350) of Typar skyward over the farm for about 5 minutes landing them finally on the tallest tree around. So far only one piece has been recovered. It was quite a sight! Without row covers, we would be having serious problems with both flea beetles and root maggot. Some cuke beetles have been spotted. Early transplants of tomatoes and summer squash and some direct seeded cucumbers were put out earlier this week under row covers. our irrigation lines follow us across the fields as we put out transplants and direct seed. It's really dry. (Hadley, MA)

Cold nights & dry soil slowing crop growth. On the other hand, few weeds so far. Hands starting to cramp from stamping checks from overwhelming bedding plant sales. Gardeners keep trying to push the season, many now returning to replace frosted tomato plants. Why don't they listen to their ag extension agents? Greenhouse tomatoes starting to ripen, much needed rain looks like it's coming this week for field crops. (Dummerston)

I think of June as flea beetle month. They seem to do better and be more prolific when the weather is hot and dry. Early June is also big on cucumber beetles. Since our soils can be a bit cool, I start even the winter squash in the greenhouse. This as well as giving me a sure stand if germination is bad, gives me a jump on the weeds and a jump on the cucumber beetles. May was hit and miss in the rain department. We had to irrigate some, but there wasn't much in the fields yet and small plants have a low water demand so it wasn't too bad. The potatoes are up, and because we rotate them the Colorado potato beetles will have a hard time finding them at first. I don't expect to see any need to spray for CPB before about June 23. (Starksboro)

We have irrigated all early greens, garlic, and even the corn seed to ensure germination. So far with good surface water levels and all irrigation systems running (no small feat) our crops look pretty good, with the exception of an early carrot planting that germinated weakly due to lack of moisture. Big blossoms on strawberries, potatoes just emerging, broccoli and cabbage under row cover starting to grow. Early tomatoes planted late last week and row-covered, leeks being transplanted today. Plenty of good lettuce in the field. No major pest problems to report. CPB not seen yet, flea beetles controlled by row cover, and cut worm not a big problem yet, although this is the week we usually see him heat up. Our first CSA distribution will be June 5 and until then we're planting and getting all harvest and distribution systems in place. (Amherst, MA)

PRECIPITATION: Weekly totals, week ending:
4/17 4/24 5/1 5/8 5/15
St. Johnsbury .26 .05 .05 .59 .20
Morrisville .15 .07 .01 .69 .13
Montpelier .23 .05 .02 .67 .10
Burlington .31 .00 .00 .59 .01
Rutland .08 .01 .04 .84 .00
Springfield .31 .05 .04 .60 .02
Bennington .18 .02 .00 .92 .02

4/24 5/1 5/8 5/15
St. Johnsbury 0 2 87 103
Morrisville 0 2 80 92
Montpelier 0 3 79 90
Burlington 3 27 124 141
Rutland 0 7 88 99
Springfield 0 5 73 88
Bennington 1 4 82 94

TOPSHIELD is a trichoderma bio-fungicide that BioWorks (the company that makes T-22 and Root Shield) is seeking to register for above ground application to a variety of crops for control of fruit and foliar diseases. According to a company rep, the product will be approved for use on all crops in the greenhouse any day now, with 0 hour REI. On the outdoor crop uses they are still debating with EPA, which will probably require a few more short term studies. So it is unlikely that outdoor uses will be approved in time for this growing season. There is strong data showing that when sprayed on foliage the product can control botryis and powdery mildew on several different crops. Joe Kovach of Cornell has also done work showing that bees can be used to deliver the material to flowers to control botrytis on small fruits. OMRI (organic materials review institute) has approved BioWorks products for organic certification.

IMPORTED CABBAGE WORMS (larvae of white cabbage butterflies) are the most common of the early "worms" that feed on the foliage of crucifers. These insects are especially susceptible to Bacillus thuringiensis (Bt) products (Dipel, Javelin, Agree, XenTari, and others), and these Bt-based insecticides do not kill the natural enemies that help to slow the buildup of other pests such as diamondback moth. Where sprays are needed early in the season, rely on Bt whenever practical. The threshold for treatment in cabbage between transplanting and cupping is 30 percent of the plants with 1 or more live larvae (of imported cabbage worm, diamondback moth, or cabbage looper); in broccoli and cauliflower prior to heading, the threshold is estimated at 50 percent of the plants with 1 or more live larvae. (Rick Weinzierl, Illinois extension)

GRAY MOLD is a common and serious diseases wherever strawberries are grown. It is caused by the fungus, Botrytis cinerea. The disease thrives during prolonged rainy and cloudy periods just before or during harvest, and on dense, lush, foliar growth. Unless suitable controls are used, frequent irrigation for frost control can lead to serious losses; greatest losses occur from blossom infections. Fruit infections often start on injuries to the flower stalks (pedicels) and caps (sepals), on green fruit damaged by frost, or where dead petals adhere to the developing fruit. Young blossoms are very susceptible to infection. One or several blossoms in a cluster may show blasting (browning and dying) that usually extends down the pedicel. Light gray masses of dusty spores soon appear and are easily dislodged and carried by air currents to other blossoms. Such infections are most common in well protected areas of the plant, where the humidity is high and air movement is poor.
Berries resting on soil and touching another decayed berry or a dead leaf in dense foliage are commonly infected. Fruit infections appear as soft, light brown, rapidly enlarging spots (see figure). The berry soon dries out, turns a darker brown, "mummifies," and is covered with a gray, dusty powder the spores of the Botrytis fungus. Immature berries may develop infection, but they become more susceptible as they ripen. The disease is often not detected until berry picking time, when many soft, brown, rotted fruits are found. Pickers handling infected fruits will spread infection to healthy fruit, causing good berries to become a rotted mass within 48 hours after being picked.

The gray mold fungus overwinters as many minute, irregular, black, fungal bodies (sclerotia) and as dormant mycelia on many kinds of plant debris, such as dead strawberry leaves, stems, and fruit, and even on annual weeds in the strawberry patch and adjoining fence rows. As spring approaches, these sclerotia produce large numbers of microscopic spores (conidia). Wind, splashing water, and human activity spread the conidia throughout the strawberry patch, depositing them on blossoms, stems, young fruit, and leaves. Parts of the strawberry plant may become infected within three hours. Temperatures between 70° to 80°F and free moisture on the foliage from rain, dew, fog, or irrigation are ideal conditions for spore germination and infection. Infections may occur at lower temperatures when plants are wet for longer time periods. The fungus usually attacks through dying, dead, or injured petals, stamens, flower stalks, berry caps, or other plant tissue. Fruit infections commonly originate at the stem end. The Botrytis fungus can penetrate the unbroken skin of the strawberry fruit. One affected berry may contaminate many others in the field or even after fruit has been harvested.

Several strawberry cultivars, which include Canoga, Guardian, and Honeoye appear to be partially resistant to gray mold. Under certain conditions, however, these cultivars may also become infected. Cultivars that produce the most exposed fruit suffer the least damage.
Proper spacing of plants and timing of fertilizer applications are important preventive measures. Avoid wide, matted rows of densely spaced plants. Narrow the row to 8 to 12 inches at renovation. Apply fertilizer in the summer on the basis of a soil test. Heavy applications of nitrogen fertilizer in the spring produce excessive amounts of dense foliage. Thick foliage shades berries and prevents rapid drying of the fruit after wet periods, thus creating ideal conditions for development of gray mold rot. Mulching strawberry plants and row middles with clean straw or other dry organic matter or with black polyethylene sheeting to keep fruit from direct contact with the soil, reduces disease incidence. Whether plants are mulched or not, cultivate as little as possible from early bloom until after harvest.

Limiting wounding of plants slows disease spread. Whenever possible, pick fruit frequently and early in the day as soon as plants are dry. Cull out all diseased berries but do not leave them in the field. Always handle berries with care to avoid bruising. The fungus enters through wounds.
Refrigerate picked fruit promptly to control gray mold growth.

Follow a fungicide spray schedule as needed to control gray mold (see New England Small Fruit Pest management Guide). Protect blossoms, fruit, pedicels, and leaves from infection by uniformly spraying all above-ground plant parts. Preventing blossom infection may double the yield of top-quality fruit. If irrigations are used for frost control, more frequent fungicide applications may be needed. Where feasible, spray a day or two before rain is predicted. (Stephen M. Ries, Univ. Of Illinois)