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 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 , 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 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 such as lady thorough coverage is essential. Use spray water with a 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. He found no 2,4-D injury associated with leaving tion system. These plants need water at

3 treatments of a specific element to solve a specific Foliar Feeding: Will it problem brought on by a specific set of conditions, not a regular program of foliar mixtures. Therefore, general or routine use of foliar feeding products in Improve Your vegetable production is not recommended. Many of the foliar products contain N, PzOs and Vegetable Crop? KzO and are basically diluted starter fertilizer materials Peter L. Minotti supplemented with two to five micronutrients. It is Cornell University true that the major nutrients (N, P and K) can be foliage absorbed to some extent, but the amount that he following attributes of foliar feeding are gen­ can be applied is limited. Moreover, once requirements erally agreed on. Foliar nutrients can penetrate have been met with a good soil fertility program, Tthe leaf cuticle and be absorbed, plants deficient nutrient loading will not turn a good crop into a "super" in a specific nutrient will respond in some degree to fo­ crop. Marketers often argue that foliar feeding will liar application of that nutrient, minor elements are provide these nutrients when "environmental stresses" better candidates for foliar feeding than major nutrients limit feeding from the soil. When this happens, how­ and foliar feeding should always be considered as sup­ ever, growth becomes limited by the stress itself (not plemental to good soil-applied fertilization programs, just limited nutrient uptake), so any response to the never as a substitute for them. Beyond this, however, foliars will be limited until the stress is removed, after the situation presented to vegetable growers can be which time sufficient feeding from the soil can resume. confusing and controversial. If you remain unconvinced and are determined to Several foliar products on the market are aggres­ use foliars, why not leave some untreated areas for sively marketed and advertised. I feel that much of the comparison on your farm? Better yet, treat only small marketing literature is very misleading. It goes some­ areas and compare results to the untreated areas. In the thing like this: unlikely event that you do obtain a response, it would Leading and progressive growers are supplementing be wise to reexamine your soil fertilizer program to good soil fertilizer programs to include foliar nutrition, make sure that it was not lacking. You can also have a and they are getting better yields and higher quality. complete nutrient analysis performed on your growing Sound management and a total crop nutrition program, cropd(b12 dto 15 ele~ents) at~ veryhreasohnab!e cost.bThis ( ~ which includes foliar feeding, is increasingly critical in cou 1 e one anyume, not JUSt w en t ere ts a pro 1em. ..,; today's climate of ever-narrowing profit margins." The information, along with the soil test, can provide a g good indication of whether there is any likelihood These advertisements leave one with the feeling that of response to foliars in subsequent seasons and, if so, if foliar feeding is not a regular part of the fertilizer which element or elements are involved. program, potential profits 'are lost. Yet, general, indis­ criminate use of foliar nutrients and "shotgun" foliar mixtures, when soil deficiencies do not exist, waste time and money and decrease profit margins. On the other hand, foliar feeding can be useful as an emergency treatment when a minor element deficiency is probable and, for one reason or another, corrective action was not taken in planning the soil fertilization program. Such situa­ tions are infrequent, and when they do occur, the factors usually involved are undesirable soil pH and a vegetable with a high requirement for a particular micro­ nutrient whose availability is restricted by the undesirable pH. In such a situation, we are looking at

4 HACCP sounds complicated and time consuming, Food Safety at Retail but it is essentially what you are already doing or should be doing. oVegetable Stands The vegetable grower should be able to recognize hazards and be aware of potential risks. For example, Kenneth N. Hall because you know farm manure can carry pathogenic University of Connecticut Extension Food Specialist bacteria, you should use it on a field that will not be used for food production that year. The HAZARD is ost of us with a farm or garden background the manure, the CRIT!CAL CONTROL POINT is the have at one time or another eaten a vegetable field and the CRITICAL LIMIT is not to use the field Mdirectly from the garden and thought the proc­ for vegetable productior. for one year. A similar situa­ ess was safe. You may have picked a cucumber or to- tion could be made for dropped apples. However, here mato and perhaps wiped the surface with your hand or the HAZARD is the possibly contaminated apples and clothes, or wiped the earth from a carrot before eating. the CRITICAL CONTROL POINT is to use dropped These procedures have been passed on for generations apples for cider that is to be pasteurized. If you do not or self-learned and, therefore, we know they are safe. have pasteurizing facilities, it may be necessary to sub­ But are they really safe? contract the service or sell the apples to someone who During recent years we have heard of Listeria has pasteurizing facilities. monocytogenes associated with cabbage, several different The U. S. Center for Disease Control (CDC) reported species of Salmonellae associated with melons and in the June 28 issue of the Journal of the American Medi­ tomatoes, and Escherichia coli 0157.H7 associated with cal Association on the dangers of pets in food prepara­ apples and apple cider. tion areas. CDC dealt with bathing lizards, snakes and You may ask why the problem. Prior to the 1980s, turtles in food preparation areas. The recommenda­ listeriosis was primarily an disease and, there­ tions were prompted by reports from 13 states citing fore, a concern for veterinarians. Now it is known as a infections caused by unusual Salmonella serotypes. All zoonotic disease, which means it can be transmitted patients had direct or indirect contact with reptiles and from to humans. Sheep manure containing identical serotypes were identified in both patients and Listeria was spread on a field where cabbage was raised, pets. It is well known that reptiles, dogs, cats and other Q the cabbage was placed in cold storage, ~ole slaw was pets carry diseases that can contaminate food. It is a good · made, consumed and humans became stck. Manure practice to keep animals of any kind away from foods. from other animals used as fertilizer in production of Processing of foods in the home for sale has not other vegetables also has been associated with several been a major problem in Connecticut, because state cases of food borne illness. In the case of apples and laws prohibit it, with the exception of jams and jellies. apple cider, it was thought that dropped apples had These can be made and sold at a farm. Some states been contaminated by wild bird or animal droppings. have more lenient laws and, consequently, there exists The vegetable grower can minimize the likelihood a greater likelihood for problems from issues already of causing foodborne illness with produce to be sold at mentioned and from the food handler. retail outlets by being conscious of the risks and by Staphylococcus aureus is a cause of food poisoning as taking steps to minimize those risks. The U.S. Depart­ opposed to food infection which is caused by live Sal­ ment of Agriculture, the Food and Drug Administra­ monellae, Listeria or E. coli growing in humans and tion and most professional organizations associated causing infection. Staphylococcus aureus is a bacteria with food production, processing, distribution and that is common with humans who have pimples, boils utilization are promoting the concept of HACCP or open sores. It can grow and produce entrotoxins in (Hazard Analysis Critical Control Points). This is a as little as two to four hours under optimum conditions, seven step procedure for: and this toxin is not destroyed by normal cooking tem­ peratures. The CRITICAL CONTROL POINT here 1. Identifying Hazards and Assessing Risks are the food handlers and the CRITICAL LIMIT is 2. Identifying Critical Control Points that any open sore should be properly covered, e.g. use plastic gloves, or the individual with sores should not 3. Establishing Critical Limits handle food. 4. Establishing Monitoring Procedures Growers should remember that vegetables can be a 5. Establishing Corrective Action direct or indirect source of pathogenic bacteria and so cause foodborne illness. Consequently, care should be () 6. Establishing Record Keeping System taken by both food producers and handlers to mini­ 7. Verifying the System is Working mize the likelihood of unsafe food.

5 Cornucopia-Fest'95!

College of Agriculture and Natural Resources Open House September 9, 1995, 10:00 a.m. to 4:00p.m. University of Connecticut Storrs, Connecticut

*Cjuided tours of college facilities, including research labs. *Demonstrations-milking, food safety, remote sensing, weather station, horse and others. * Introduction of Cornucopia ice cream flavor. * Sick plant clinic. *Commercial vendors.

*Food. r.------~ *Much more. CORNUCOPIA-f~5

Good for one FREE small cone

V,1/id Sa1urd.1J. &pumb" 9. 1995 u11f;o

needs only one to complete its life cycle. When the Good Guys in the parasite kills the host, it is termed a . Ectoparasitoids feed on the host from outside the host's body, while endoparasitoids are inside the Potato Patch host's body. Rose Hiskes Just who are these good guys? There is one near University of Connecticut Extension Horticulturist relative of the spiders, two beetles, one fly and two true bugs that live in the Northeast and in some way he (CPB) usually takes reduce the CPB population. See theWANTED poster center stage when the topic of potato-related in­ on page ~ for line drawings of each. Tsects comes up. However, there are CPB preda­ tors and parasites native to New England that deserve The spider relative is a daddy-long-legs, in the a place on the stage. In fields where integrated pest family Phalangidae Phalangium opilio. The body of the management (IPM) is practiced and B.t. and pyre­ adult is just over 1/4-inch long. The adult is a predator throid insecticides such as Novador and Ansana are ofCPB eggs and small larvae and feeds at night. Table used, these beneficial insects are showing up. 1 shows that one adult eats approximately ten CPB eggs per-day. When talking about beneficial insects, what exactly is meant by predator? A predator has a short-term The two beetles that prey on CPB in the Northeast association with its prey and kills many of them in are the twelve-spotted ladybeetle, Coleomegilla macu- order to complete its own life cycle. A parasite feeds lata, and a , grandis. The lady beetle L~ ) on its host over a longer time period and generally is oblong, about 3/16-inch in length and is a pale red

6 1 Table I. Consumption ofCPB by endemic predators • this bug prey on all stages of CPB except pupae. They insert their piercing-sucking mouthparts into the CPB Large larvae and withdraw body fluids. They are able to get Eggs per day per day between the sclerites on adult CPBs and feed on them : Predator (mean± SE) (mean± SE) as well. Table 1 shows P. bioculatus to be almost as Lebia grandis adults 47.38 ± 2.07 1.91 ± 0.55 voracious as Lebia grandis with regard to CPB eggs. 7.95 ± 0.74 0.33 ± 0.10 adults The second u::1e bug that preys on CPB in the Northeast is the spined soldier bug, Podisus maculi­ Perillus bioculatus 39.00 0.21 5th instars ventris. Adults are 1/~- to 3/8-inch long, pale brown in color with two spines !)rejecting from each side of the Podisus maculiventris - 1.00 5th instars pronotum, immediately behind the head. The silver eggs are laid in bunches on the upper leaf surface of Phalangium opilio 9.63 ± 3.25 0.00 adults potato. Upon hatching, larvae are red and black, but as 1Groden 1988. they grow, the color pattern changes to include orange and white. color with 12 black spots on the wing covers. The As with the two-spotted stinkbug, both adults and adult preys mainly on CPB eggs, first and second in­ nymphs of the spined soldier bug prey on all life stages star larvae (Table 1). As the season progresses, they of CPB, except pupae. In growth chamber experiments leave potato plantings if aphid prey are available else­ at temperatures of 16°C (61 °F) and 28°C (82.5°F), where. Lady beetle larvae, which are grayish black P. maculiventris nymphs ate up to 5.2 CPB eggs in a with red dots and look like miniature alligators, also 24-hour period (Hiskes, 1994). This number is low prey on CPB eggs. because both tern- peratures are less than optimum for The ground beetle, Lebia grandis, is 3/8-inch long P. maculiventris activity. and has a rusty orange head and body, with irridescent So, as you walk your fields this summer, be on the blue wing covers. It is nocturnal and, in contrast to lookout for these good guys and do everything you can other ground beetles, searches for food in the plant to make them work for you in your potato patch. Keep canopy. The adults prey on CPB eggs and all larval them in mind when choosing a pest management ins tars. L. grandis lays eggs singly on the soil surface. strategy. Yu (1988) reported that Podisus was more sus­ / tAfter hatching, the larvae burrow into the soil where ceptible to organophosphate and carbamate insecti­ ""-· they are ectoparasitoids of CPB pupae. As you can see cides than its prey, but the reverse was true with from Table 1, L. grandis adults are voracious, eating pyrethroids. Products like Asana, Ambush and Pounce approximately one CPB egg mass or two large larvae are effective if applied properly. Because the B.t. per day. Groden found that L. grandis appears at peak products are very specific in what they control, they egg laying by overwintering adults. Since CPB larvae also conserve native beneficials. M-Trak and Novador from overwintering adults cause most of the defolia­ effectively kill small CPB larvae. tion, L. grandis, when present in sufficient numbers, can protect potato foliage when it is needed most. References The fly that parasitizes CPB larvae is in the Groden, E. 1988. Natural mortality of the Colorado Tachinid family, Myiopharus doryphorae. The adults are potato beetle, Leptinotarsa decemlineata (Say). PhD reddish or grayish brown with fuzzy bodies and are dissertation. Michigan State University, E. Lansing. 3/8- to 1/2-inch long. The female injects the maggot, an endoparasitoid, into mature CPB larvae with her Hiskes, R. 1994. Evaluation ofPodisus maculiventris ovipositor just before they burrow into the soil to (Hemiptera:Pentatomidae) for control of the Colorado pupate. The maggot feeds on the CPB pupae and Potato Beetle, Leptinotarsa decemlineata, (Coleoptera: pupates in the empty larval skin. The adult fly then Chrysomelidae) on potatoes groum under row cover. MS emerges from the soil. Hoffman and Frodsham (1993) thesis. University of Connecticut, Storrs. say that adults might also feed on CPB larvae. Since Hoffman, M. and A. Frodsham, 1993. Natural females lay as many as 1,000 eggs, up to that many enemies ofvegetable insect pests. Cornell Cooperative CPB pupae can be controlled by one adult female fly. Extension. The true bugs that prey on CPB are all in the shield Yu, S. J. 1988. Selectivity of insecticides to the bug family, Pentatomidae. The two-spotted stinkbug, spined soldier bug (Heteroptera:Pentatomidae) and its Perillus bioculatus, preys almost specifically on CPB. Lepidopterous prey. Journal of Economic Entomology Adults are 3/8- to 1/2-inch long with black areas out- 8 (1): 119-122. · ~)lined in bright red or yellow. Adults and nymphs of .... pageS

7 WANTED J Spined Soldier Bug 12-Spotted Lady Beetle Two Spotted Stinkbug

Daddy-Long-Legs Lebia grandis (Ground Beetle) Tachinid Fly For Control of the Colorado Potato Beetle

430254 University of Connecticut Nonprofit Richard A. Ashley Organization 1376 Storrs Road, U-67 U.S. Postage Storrs, CT 06269-4067 PAID Permit No.3 Storrs, CT