VERMONT VEGETABLE AND BERRY NEWS, August 1, 2002
Compiled by Vern Grubinger, University of Vermont Extension
(802) 257-7967 or vernon.grubinger@uvm.edu
www.uvm.edu/vtvegandberry

REPORTS FROM THE FIELD (as of July 29)

(Westminster) Wow! It's hot, it's cool, it's too dry, too wet. What kind of weather didn't we get this year? Anyways, stuff is growing like crazy, finished getting the garlic crop in, it's huge! Pumpkins setting up well, starting to see the gray squash bugs running around, time to spray!

(Wolcott) Seed crops are all doing well and have caught up after a slow start because of all the rain and clouds. The first crops we have harvested are onion and chive seed, and several perennial and biennial flowers. The mizuna seed crop will be ready by early August with broccoli and pea seed crops ready by mid to late August. Tomatoes will be coming soon too. Spinach and radishes continue to surprise all visitors to the fields (the spinach in 3 to 4 feet tall and the radishes are over 5 feet). With a new NOFA-VT grant I have been visiting many growers who are interested in seed production and helping them with equipment, scale questions, marketing, economics, variety choice, isolation possibilities as well as production techniques.  If you're interested in getting a visit or a phone call regarding seed growing call Tom at 802-888-1800.

(West Rutland) Veg sales going well. Rain has helped a great deal as has irrigating. Picked my first plastic corn last week.

(S. Royalton) We are getting just enough rain to keep things going.  Melons look great and should be picking them any day now. Potatoes are big enough and I'll be mowing them down soon.  I have some areas that have serious scab, ouch!  I have just started picking field tomatoes.  I've grown the most prolific crop of early blight on the tomato plants that I've ever had. Sweet corn will also be in this week.  I've decided that the only way to do organic sweet corn from seed early in the year is to double the planting rate.  The germination of my first planting (mid-May) is always terrible.

(Killington) Floating row cover has been very helpful this year. Asian greens have less flea beetle and the eggplant has benefited as well. Lots of green peppers but I only pick red peppers since they are worth more. String beans are ready a week later than I like. Sugar Snaps are still coming strong. Have started sugar snap transplants in the greenhouse. They'll be ready to go in the ground when the producing plants stop. Also started spinach transplants. Picking Jet Star and Beefsteak tomatoes from the hoop house. Great flavor.

(Putney) The Iroquois white flour corn in our 3 sisters' field is growing well. Scarlet runner, romano, kentucky wonder, and strawberry pole beans along with butternut squash and sugar pumpkin are also growing in the mounds. The beans have started their journey up the corn stalks and the squash are spreading their leaves. On half the field, we side-dressed the mounds with fish emulsion and we broadcast dry fertilizer on the other half to compare results. After the rains, everything has perked up.

(Argyle NY) Farmers' market sales are doing real well now as summer is in full swing. Back at the farm we are battling the cuke beetles (most we've ever had) and purslane. Irrigation is doing its job helping us to produce some nice lettuce and spinach in spite of the heat. Harvesting tomatoes (mostly heirloom) and blueberries. We split the rhubarb patch and have lots of extra clumps if anyone is looking to start or increase a patch--great money-maker per square foot! (sparnold@capital.net) Still looking for good organic control for cuke beetles and leafhoppers.

TWILIGHT MEETING REMINDER
Tuesday August 20, 5 to 7 pm  - Melons and Mixed Vegetables at Hurricane Flats, S. Royalton

Hurricane Flats gets its name from the wind that funnels through the farm's river bottom land where for seven years Geo Honigford has been growing a diversity of organic mixed vegetables on a handful of acres. He has built up a reputation for good melons. He direct markets almost everything he grows, and except on market day, it is a lean and mean one man operation. Economically the farm has been successful, and uses a lot of hand tools along with a few tractor toys.  Directions: Take exit 2 off I-89 (Sharon). At bottom of ramp go south on Rt. 132  (from the north a right turn, from the south a left). In 100 yards go right on Rt.14. In 1/4 mile turn left, over bridge across the river, on Back River Rd. The farm is 3.5 miles up on the right, you'll see a red barn at the end of a big field.  Co-sponsored with NOFA-VT. $5 registration fee for members of the VV&BGA or NOFA members; $8 for all others.

IT'S TIME FOR BERRY LEAF ANALYSIS

Foliar analysis is the key to making optimal fertilizer recommendations for perennial fruits. A minimum of 50 leaves from raspberries or strawberries, and 80 to 100 leaves from blueberries  should be selected for each analysis. Do not mix leaves from fields with different soil types or management histories. Do not combine leaves from healthy plants with plants that are not growing well. Strawberry samples should be taken from the first fully-expanded leaves after renovation, about July 15 to August 15. Raspberry samples should be leaves from non-fruiting canes taken between August 1 and 20. Blueberry samples should be leaves taken during harvest, from July 15 to August 15.  Place samples in sealed paper bags, labeled with field names. Send a check for $20 per sample, made out to UVM Ag Testing Lab, to: UVM Ag. Testing Lab, Hills Building, Burlington VT 05405-0082.

THE SCOOP ON BLACK VINE WEEVIL CONTROL IN STRAWBERRY
(from info supplied by Richard Cowles, CT Agricultural Experiment. Station; Peter Shearer, Rutgers Cooperative Extension; and others)

The larvae of several kinds of root weevils can cause serious damage to strawberry roots, leading to reduced yield and in at least one case this year in southern Vermont the complete demise of a previously healthy field. Black vine weevil (BVW) is probably more common than strawberry root weevil or rough strawberry root weevil in New England. The life cycle and management of these weevils are the same. Their larvae are whitish, crescent-shaped larvae and 1/4 to1/2 inch long with no legs. Adults emerge and feed from May through August, laying eggs as late as October that hatch and overwinter as larvae. Adult feeding causes characteristic scalloping or notching of the leaf edges, but rarely does this cause economic damage. (Feeding on the interior of the leaf, causing holes, is caused by Asiatic garden beetles or Japanese beetles.)

Adults weevils hide in the crowns during the day and feed at night. They are not easy to kill with insecticides so a better strategy is to kill the larvae with applications of beneficial nematodes. If adults are numerous (i.e. more than 50 out of 100 leaves sampled across the field have notching) then a spray may be warranted. The pyrethroid bifenthrin (Brigade) provides some control if used at the highest labeled rates. The best timing for this spray is at night during the peak feeding activity of adults, before they start laying eggs, or about 1 week before harvest ends. Neem-based products containing azadiractin (such as Aza-Direct) may be acceptable for organic production, and while neem will not kill the adults it can disrupt egg-laying if applied at high rates at least twice. While Admire is very good for controlling some white grubs it is mediocre against Asiatic garden beetle and very poor against BVW.

Although bifenthrin claims to kill spider mites, many twospotted spider mite populations are resistant to pyrethroids. Spraying this product or other pyrethroids usually exacerbates spider mite problems by selectively killing off predatory mites. Growers challenged with black vine weevil problems should plan well ahead, and use horticultural oil (SunSpray UltraFine Oil) early in the growing season. If applied with an airblast mist blower, oil can be inexpensive, effective, and non-toxic to predatory mites. This strategy can then reduce the risk of spider mite problems later. Be sure to use oil about 2 weeks before any Captan sprays, because the two products are extremely phytotoxic. Alternatively, Brigade may be applied with oil 2 to 3 days after mowing the foliage during renovation. This approach should jointly control spider mites and root weevil adults.

The key to successful use of beneficial nematodes is sufficient time for multiplication of the nematodes in hosts (weevil larvae) and dispersal of nematodes throughout the soil. Early- to mid-May application has given excellent results, especially when the numbers of larvae of the next weevil generation are evaluated in the autumn. Research in CT, NJ and elsewhere has shown that the appropriate nematode species properly applied can effectively infect and suppress weevil populations. Heterorhabditis bacteriophora (Hb) appears to be the best candidate for control of root weevils when the soil temperature is above 60 degrees ('J-3 Max Hb' from The Green Spot; 'GrubStake HB' from Integrated Biocontrol Systems; 'Larvanem' from Koppert Biologicals). Beneficial nematodes can also be applied in late summer (August 15 - September 1), and in that case, Steinernema feltiae ('Nemasys' from Griffin Greenhouse Supply, 'Gnat Not' from Integrated Biological Control Systems, 'Entonem' from Koppert Biological) should be considered in northern locations since it tolerates cooler soil temperatures and completes its life cycle so quickly. Other beneficial nematodes may also control weevils but these 2 species were most commonly found established in CT strawberry fields.  There is no point in applying beneficial nematodes in early or mid-summer since few larvae are present.

Nematodes are living organisms and they can be killed if they are misapplied. Order nematodes ahead of time and be ready to apply them through a sprayer or irrigation soon after they arrive, refrigerating if delay is necessary. Do not apply nematodes using a sprayer with a piston pump. Use clean equipment, removing all screens finer than 50-mesh. Apply nematodes in early morning or evening in a high volume of water to already moist soil, pre-irrigating if needed. Apply another 1/4 inch of irrigation after application to wash them onto and into the soil. Although references suggest rates of several billion nematodes per acre, I found researchers and suppliers recommended 250 (if banded in the row) to 500 million per acre, at a cost of about $100 to 200 acre depending on volume and source. Green Spot says their formulation requires lower numbers of nematodes but the cost ends up about the same. Ironically, nematodes probably work best in the worst weevil-infested fields. High populations of weevil larvae allow explosive growth in nematode populations, while low populations of larvae may not permit efficient nematode reproduction. Strawberry plants can recover their vigor remarkably well if crown feeding has not occurred and diseases haven't taken over the roots.

Root weevils cannot fly, so they infest new plantings by wandering into fields from surrounding weedy and woodland vegetation, or in large numbers from recently plowed, infested strawberry plantings. Even plantings several hundred feet away can become generally infested as a result of mass migration from plowed fields. A good rotation program with substantial distance between strawberry fields can help to manage root weevils. Also, when turning under old, infested strawberry plantings, it is critical to leave a row or two at the perimeter of the field as a trap crop to protect other plantings. Adult weevils will be intercepted in these rows before they leave the field and thus lay their eggs where the larvae will not do any damage. At the end of the season the trap rows should be turned under prior to planting winter rye. Do not spray the trap rows as this may repel weevils and result in more migration to other fields.

Some Beneficial Nematode Suppliers:
The Green Spot: 603-942-8925 or www.shopgreenmethods.com
Griffin Greenhouse Supplies: 978-851-4346 or www.griffins.com
Integrated Biological Control Systems: 888-793-4227 or www.goodbug-shop.com  Koppert Biologicals: 800-928-8827 or www.koppert.com
 
(Mention of pesticides and biological controls is for information purposes only; no endorsement of materials or brands is intended. Always read and follow instructions on the label.)