Volume 95-7 .July 1995 Rirhmd A. A.rhleJ• Pat.ry IV El'an.r . After the Harvest Not711all L. G,mthier William Lord Jude Bourher· Rou Hi.rke.r 3 U11i~·er ·.rity of C.lmneaimt Foliar Feeding: Will COLLABORATORS it Improve Your Maine Vegetable Crop? lflilfred Et-bardt Peter L. Minotti David 1-!tmd/ey 4 Massachusetls john C. f/uu:e/1 Jr. Pest · ., .,;.a.;· "~ :'"'; "' or R. Aldt•n Aliller Food Safety at Retail Vegetable Stands rrt:::~:~, 7~~c~ New Hampshire 0 Growers William G. Lord Kenneth N. Hall Otho S. \f/e//.r 5 Dr. Vern Grubinger University of Vermont Extension System Rhode Island lfli/1 RquuldJ Good Guys in the rganic certification, contrary to popular be­ Vermont Potato Patch lief, does allow pesticides to be used in vegeta­ ble and berry production. However, the Vem Gmbiuger- Rose Hiskes 0 selection is limited compared to conventional pro­ This publiacion 6 duction, and it excludes most, but not all, manmade is produced materials. The federal Organic Foods Production Act through che combined of 1990 mandated the development of a national list efforts and of allowed materials. This list is due to be published sources of the later this year. peracive Extcn- t--.!l organizations With a relatively small array of pesticides to work v--· ' uf the N= England with, organic growers must emphasize the use of Land-Granc universicies. cultural practices to minimize pest problems. Practices such as crop rotation, sanitation, stress avoidance and selection of resistant varieties are the cornerstone of organic, as well as conventional, pest management. .... page 2 Soaps work by smothering soft-bodied insects like Pesticides aphids or thrips. Application directly onto exposed .... page 1 insects is critical to good control. Soaps can be phyto­ toxic to some crops and harmful to some beneficials. When organic pesticides need to be used, the choices include botanicals, microbials, synthetics and Horticultural and other dormant oils are petroleum- 't minerals. Botanicals are plant-derived materials such based but are an organically-allowed means of smother­ as rotenone, pyrethrum, sabadilla, ryania, etc. Nicotine ing scale and other insects. There is good evidence products, although natural, are not permitted due to that horticultural oil in combination with bicarbonate their high mammalian toxicity. Botanicals are gen­ salts (such as baking soda) can prevent powdery mil- erally short-lived in the environment, being broken dew on crops like cucurbits. All that's missing is a down rapidly in the presence of light and air. Thus, label for the use of baking soda as a fungicide. they provide pest control for only a day or two. Ryania Minerals such as sulfur and copper are the primary and sabadilla may have some additional residual organic fungicides and bactericides used to prevent activity. Botanicals are generally broad spectrum, so disease in the field. Some available formulations are they kill beneficial insects too. Bordeaux mixture, tribasic copper, copper hydroxide Some newer botanical insecticides include products (Kocide), cupric oxide, copper sulfate, elemental made from extracts of neem tree seeds. Azatin and sulfur, calcium polysulfide (lime sulfur) and copper­ Align are labelled for many vegetable crops. Azadirach­ zinc mixtmes. With a good spray program and cultural tin, the active ingredient, has a very low mammalian practices that maximize leaf drying, organic growers toxicity. It works by inhibiting development of may achieve effective prevention. In some cases, as immature stages of many insects and by deterring with bramble and blueberry "blights", these may be feeding by adults. the materials of choice. Use these products with caution because of potential phytotoxicity, especially Microbial pesticides, formulated from microorgan­ with temperatures over 80°F. isms or their byproducts, tend to have advantages over the botanicals in that they are safer to use and are Diatomaceous earth is really a biological, as it is more selective in what they kill, so beneficials are not composed of one-celled diatoms, the "shells" of which harmed. Bacillus thuringiensis or B.t. is perhaps the act as a mineral dust which dries certain soft-bodied most widely used type of microbial insecticide. B. t. insects. It is more widely used in post-harvest applica­ products contain a toxin made by a bacterium. B.t. has tions than in the field. greatly expanded organic pest control effectiveness for Although disinfectants are not typically considered insects like Colorado potato beetle, the cabbage worm pesticides, they are important to horticultural complex and corn borer (see June 1995 Grower). produc-tion. The synthetic materials, chlorine (bleach) The major types of B.t. are the 'kurstake' strain for or hydrogen peroxide are allowed organically as dilute caterpillar pests (Dipel, Javelin, Thuricide, MVP, etc.) solutions to disinfectant greenhouse surfaces and tools. and the 'San Diego' or 'tenebrionis' strain for potato Other synthetics may be permitted in special applica­ beetle larvae (M-One, M-Trak, Beetle Beater, Novador, tions such as pheromone traps for monitoring insect etc.). pest populations, although the permissibility of this use varies among certifying bodies. For B.t. to be effective, you must use the right strain for the pest and apply it when small larvae are actively The so-called "beneficial" insects include : '\.}.. feeding. Because B.t. must be ingested by the pest, predators and parasitoids such as lady thorough coverage is essential. Use spray water with a beetles and various wasps, as well as certain& j/ pH between four and seven for best results. nematodes that are used for insect control. These are all allowed organically. They .' .. Other microbials are available that work as fungi­ are classified by regulatory agencies as cides, such as Mycostop, a soil drench derived from biological controls, not as pesticides. Most suppliers of Streptomyces fungus, and Gliogard, derived from these organisms provide good information on how to G/iocladium fungus. Both these products are labeled to best use them. control some root rotting organisms that cause damping-off and similar problems in seeded crops. With organic pesticides, as all others, read the label carefully to be sure it applies to the crop and pest in Synthetics available to organic growers include soaps question and to learn the most effective means of and horticultural oil. Soaps are fatty acids of potassium application. Remember that labels may change from salts, which are formulated to be both insecticides year to year as crops and pests are added or withdrawn, (M-Pede, Safer's Soap) and herbicides (Sharpshooter). or new application procedures developed. ~ The latter is not allowed by all certification groups. / z tions are a problem. At renovation, deep cultivation is After the Harvest important. If soil compaction and drainage are prob­ lems, this is a great time to run a chisel plow down William Lord aisles to fracture the compacted layer, then till the soil UNH Cooperative Extension Frnit Specialist deeply, ensuring thorough incorporation of residual mulch material into the soil. How aggressively should 'm not sure I have ever seen a better strawberry year you narrow rows during this process? I like to adjust in New Hampshire. Even growers in Coos County, my attack to the vigor of tne block. If a cultivar is a Iwhere irrigation for frost control as late as July 1 is poor plant maker, try a final plant row 16 inches, but if possible, didn't lose a minute of sleep to frost worries another cultivar is a vigorous, agGressive plant maker, this year. Fruit quality, especially flesh firmness and narrowing to 10 or 12 inches m:1 y make more sense. size, has been spectacular. This is a great time to mulch strawberry crowns How do we get a repeat performance in 1996? Obvi­ with about an inch of soil. This soil mulch will pro­ ously, in agriculture there are no guarantees. The one vide the crown new rooting opportunities, roots that thing we simply have no control over is the weather, will fuel crown growth and fruit size through the next but we can try to set things up so we can make the most year's harvest. The crown is, after all, a stem. Yes, this of what we are dealt. Bed renovation is a key first step. stem doesn't grow much during the year, but it does The renovation sequence has been well documented, grow, and the older, lower portion of the crown and its but it is worth taking a second look as we get started. roots die. Providing soil, not chopped mulch, into which this new crown can root will encourage healthy, Control Broadleaf Weeds with 2,4-D vigorous growth. Most tillers can be adjusted to allow If broad leaf weeds such as dandelion and shepherd's loose soil to splash up around these crowns during the purse are problems, an application of2,4-D immediately row narrowmg process. after harvest is the first step in the renovation process. Three to five days after application, the rest of the S inbar Application (if necessary) renovation sequence can begin. If annual broadleaf and grass weed control is needed and soil organic matter is greater than 2%, Sin bar Mow Foliage can be applied at this time. Be sure to follow labeled ~ ) Mow strawberry foliage an inch or two above crowns. rates carefully. Overapplication can cause significant Marvin Pritts, Cornell Cooperative Extension, has ex­ plant injury. plored the issue of whether leaf removal at renova- tion is necessary. Marvin showed that the only benefits Turn on the Water of mowing were a reduction in plant runners and plant The single most important piece of equip- t density and a slight increase in fruit size the following ment in the strawberry field is the irriga- t year.