The New Agriculture Network's on-line newsletter with seasonal advice for field crop and vegetable growers interested in organic agriculture.
Next issue will be posted September 12, 2006. Read previous issues through our calendar of issues.
Evaluating organic herbicides, summer annual cover crops and mowing for Canada thistle control
John Masiunas and Abram Bicksler
Department of Natural Resources and Environmental Sciences
University of Illinois
Managing Canada thistle in organic crops is difficult because of its extensive creeping root systems, competitiveness and lack of effective control strategies. Canada thistle control strategies can suppress thistle root system (i.e. intensive tillage), destroy the shoots (i.e. intensive mowing) or out-compete the plant (i.e. cover crops). The underlying principle for these strategies is to prevent seed production and regrowth from the roots. We conducted two studies this summer on managing Canada thistle. In the first study we evaluated materials that may desiccate thistle shoots and kill annual weeds, possibly creating a stale seedbed. In the second study we determined the ability of summer cover crops alone or combined with mowing to suppress Canada thistle.
Canada thistle desiccation with clove oil and vinegar
There are several products being sold as “all natural” or organic herbicides that may have a role in weed management in organic cropping systems. Generally these products contain vinegar (acetic acid) or clove oil (eugenol). Both vinegar and clove oil are on the USDA National Organic Program Approved Materials List and some of the products have been evaluated by the Organic Materials Review Institute (OMRI), but may be listed as restricted. Thus, you need to consult with your certifier before using any of these products. Also, in order to be used, these products may have to be registered with the appropriate state agency such as the Illinois Department of Agriculture (http://www.kellysolution.com/IL/pesticideindex.asp) or the Office of the Indiana State Chemist (http://state.ceris.purdue/htbin/nextprodp.com).
These herbicides generally claim exemption from U.S. Environmental Protection Agency regulations as minimal risk pesticides under section 152.25(g) of Title 40 of the Code of Federal Regulations. Besides containing exempt active ingredients (the chemical which kills the weed), these herbicides must include minimum risk inert ingredients. Exempt minimum risk herbicides must still have a label that lists active ingredients and their percentages. The inert ingredients must be listed, although percentages do not have to be provided. Citric acid, eugenol (clove oil), garlic, lauryl sulfate and 2-phenyl propionate are all on the minimum risk active ingredient list. Acetic acid (vinegar) is not on this minimum risk active ingredient list and manufacturers are limited in the percentage of acetic acid they can use as an active ingredient. But acetic acid is on the list of minimum risk inert ingredients, even though it has herbicidal activity.
Both clove oil and vinegar desiccate (dry-out) plant shoots. A common clove oil product, Matran 5A (EcoSMART Technologies; Franklin, Tenn.), is OMRI-approved and USDA NOP-compliant and contains 50 percent clove oil. Vinegar (acetic acid) is contained in a variety of products including Distilled White Vinegar Concentrate (National Vinegar Company; St. Louis, Mo.). The National Vinegar Company product is OMRI-approved and USDA NOP-compliant. Optimal weed control is obtained when vinegar or clove oil is applied to actively growing plants 2 to 4 inches in height. Complete coverage of leaf surfaces is essential. Broadleaf weeds with exposed growing points are better controlled than grass weeds. Use of an adjuvant (spreader sticker) can improve control of weeds with waxy leaves. Weed control is best when an application is made on sunny days with temperatures above 60 degrees F. Vinegar has been reported to burn-back perennial Canada thistle. We were interested if these herbicides could burn-back perennial Canada thistle and newly emerged annual weeds. Since any herbicide containing clove oil or vinegar does not translocate in perennial weeds, none of these products will directly kill root systems.
Table 1. Weed control from stale seedbed treatment of emerged annual broadleaf weeds, annual grasses and perennial Canada thistle. The treatments were applied on June 30, two weeks after preparing the stale seedbeds.
| 3 Days After Treatment | 10 Days After Treatment |
||||||
Treatment |
Concentration |
Broad-leaves |
Grass |
Thistle |
Broad-leaves |
Grass |
Thistle |
| ------------------------- % Control ----------------------------------- | |||||||
Control |
-- |
0 |
0 |
0 |
0 |
0 |
0 |
Flaming |
1 x |
8 |
10 |
14 |
18 |
20 |
9 |
Matran |
5% |
4 |
4 |
3 |
1 |
0 |
2 |
Matran |
10% |
14 |
14 |
6 |
5 |
3 |
1 |
Matran |
15% |
10 |
13 |
11 |
0 |
6 |
3 |
Matran |
20% |
16 |
15 |
8 |
4 |
4 |
6 |
Vinegar |
5% |
6 |
2 |
8 |
0 |
0 |
1 |
Vinegar |
10% |
10 |
3 |
13 |
0 |
0 |
5 |
Vinegar |
15% |
5 |
3 |
17 |
2 |
4 |
5 |
Vinegar |
20% |
6 |
3 |
30 |
0 |
1 |
7 |
None of the treatments provided acceptable control of annual weeds. The annual broadleaf weeds were predominately ivyleaf morningglory with some prickly sida, velvetleaf and common lambsquarters. Annual broadleaf weed control ranged from 4 to 14 percent, generally consisting of leaf yellowing and burning. At application, the ivyleaf morningglory had three to four leaves; prickly sida had six leaves; velvetleaf had two to four leaves; and common lambsquarters had four to seven leaves. These weed sizes may have been too large for weed control with flaming, Matran or vinegar. Also ivyleaf morningglory may be a difficult weed to control with these treatments. The broadleaf weeds regrew from the injury within 10 days in all treatments except the flaming.
Annual grasses were mainly foxtails and large crabgrass that had four to six leaves. Annual grass control was 2 to 14 percent. Control with higher rates of Matran, although unacceptable, was better than all vinegar rates. Other researchers have also found that annual grass control is poor with Matran and vinegar. The growing points of grasses are protected and are not killed by the herbicides. Grass also regrew by 10 days, with only flaming still causing significant injury. The poor annual weed control means none of the treatments would be acceptable to kill weeds before crop planting.
Canada thistle was affected by several of the treatments. The highest rate of vinegar (20 percent) did cause some desiccation of the thistle, but the plants rapidly recovered. It does not appear that flaming, Matran or vinegar have a role in management of Canada thistle.
Summer cover crops and mowing suppression of Canada thistle
Cover crops may suppress Canada thistle in organic cropping systems. The suppressive ability of cover crops on Canada thistle relates to their capacity to occupy ecological niches otherwise available for weed development. This occurs through cover crops out competing Canada thistle for resources such as light, water and nutrients and their releasing chemicals that suppresses the thistle. Canada thistle root carbohydrate reserves, important for plant regrowth, are lowest between late June and late August. We hypothesize that cover crops actively growing during this period may be especially competitive against Canada thistle.
Sustainable and organic farmers commonly use buckwheat as a green manure. Buckwheat quickly germinates, rapidly establishes a canopy and shades out weeds. Its best growth is during warm days and cool nights of early and late summer. Early summer is when Canada thistle root carbohydrate reserves are at their lowest. Buckwheat only reaches about three feet tall, but can be densely planted to maximize its competitiveness for light. Sudangrass fits into a summer niche when Canada thistle growth is poor. Sudangrass is a C4 species that is best able to use resources in a warm, high-light environment and produces tremendous amounts of biomass. Sudangrass rapidly closes canopy, reaching heights of 10 feet, capturing most light in an agroecosytem. Sudangrass also produces an extensive root system, which captures rainfall and immobilizes nutrients near the soil surface, making it more competitive than Canada thistle that has its roots below the plow layer.
Buckwheat and Sudangrass also produce chemicals (call allelochemicals) that can suppress the growth of annual plants. Buckwheat plants contain the allelochemicals fagomime, 4-piperidone, 2-piperidine methanol, gallic acid and (+)-catechin. Sudangrass contains the allelochemicals sorgoleone and dhurrinase. We plan future research on whether or not these allelochemicals also can suppress growth of Canada thistle.
Table 2 presents the results from our cover crop and mowing study. Canada thistle plant densities decreased by 31 percent in the no cover crop, no mowing treatment due to some shoot death due to competition with other shoots and natural biological control. Mowing further reduced thistle density and shoot biomass. Buckwheat was very competitive with Canada thistle reducing the number of shoots by 92 percent and their shoot weight to 21 percent of the fallow. Mowing reduced the effectiveness of buckwheat in reducing the thistle density probably because buckwheat did not regrow after mowing. Sudangrass alone or with cowpea was very suppressive of Canada thistle, reducing density by greater than 90 percent and shoot weight to less than 30 percent of the control. Sudangrass without mowing was effective in reducing thistle by 98 percent, but adding mowing provided a further reduction in thistle shoot weights. We will determine Canada thistle regrowth next year. We feel that both buckwheat and Sudangrass provide an option for organic farmers to suppress Canada thistle, but complete control of Canada thistle will require a multiyear program integrating a variety of management strategies followed by continual monitoring to prevent the establishment of new populations.
Table 2. The reduction in the number of Canada thistle plants from before tillage and cover crop planting to after the second mowing. The reduction in the weight of Canada thistle shoots compared to the fallow treatment without cover crops or mowing. Thistle weight has not yet been collected after the second mowing.
Cover Crop |
Mowing |
Reduction in # of thistle plants |
Reduction in biomass of plants |
|
|
% reduction |
% Fallow w/o mowing |
Fallow |
0 |
31 |
100 |
Fallow |
1 x |
87 |
13 |
Fallow |
2 x |
58 |
-- |
Buckwheat |
0 |
92 |
21 |
Buckwheat |
1 x |
83 |
10 |
Buckwheat |
2 x |
58 |
-- |
Sudangrass |
0 |
98 |
27 |
Sudangrass |
1 x |
97 |
1 |
Sudangrass |
2 x |
94 |
-- |
Sudangrass + cowpea |
0 |
96 |
15 |
Sudangrass + cowpea |
1 x |
93 |
3 |
Sudangrass + cowpea |
2 x |
98 |
-- |
Shari L. Plimpton, Ph.D., Program Manager - Industry Outreach
CIFT/EISC, Inc.
When I speak of microbial food safety to a group of growers, few imagine that I will be focusing on the safety of their field practices, particularly the soil. Understandably, many assume that harvest and post-harvest practices will be the focus. For the greatest food safety success, the emphasis should be on prevention of microbial contamination, since it has been demonstrated repeatedly that washing does not eliminate pathogenic microorganisms (those microorganisms that cause foodborne illness.) Therefore, all practices that could be a source of contamination pre-harvest, including manure management, should be reviewed with foodborne illness in mind.
Sustainable agricultural practices are touted as methods designed to prevent contamination from chemicals, pesticides and microorganisms. It is not enough to assume that if you are building a soil based on sustainable practices that you need not worry about pathogenic microorganisms. Attention must be paid to detail when handling manure to assure that the microorganisms that thrive in the resulting soil are not pathogenic. Pathogenic microorganisms do thrive in both soil (i.e. Listeria) and animal and human intestinal tracts (i.e. E.coli, Salmonella). Properly treated, manure can be an effective fertilizer. For this reason, Good Agricultural Practices (GAPs) have been developed for the entire farm operation to reduce the potential for foodborne illness from fruits and vegetables.
While most of this will be recognized as common sense, let’s review the GAPs that apply to manure management recommended by the USDA and the FDA (not to mention the GAPs program itself).
Consider the source
We recommend that you segregate manure from young animals from that of mature animals. Young animals have been shown to have higher levels of potentially pathogenic microorganisms. Also, consult your veterinarian regarding the health of your herd as it pertains to using the manure they produce for horticultural crops.
Incorporate
Whether or not you are composting, be sure to incorporate manure into the soil so the soil’s microflora can act more effectively upon the organic material you are adding.
Timing
If you do not compost, then apply the manure to fields for crops not intended for human consumption. If you must use it for crops intended for human consumption, then incorporate the manure at least 120 days (90 days if you are certain the crop will not come in contact with the soil) before the harvest of a crop intended for human consumption.
Compost
Composting is the preferred practice when managing manure incorporation into the soil, because it is effective in reducing the presence of pathogenic microorganisms (we can’t say eliminate because of the chance of some survival.) Composting, of course, has some recommendations of its own, of which I will mention a few:
- Maintain barriers to prevent leakage and tracking from both manure and compost piles.
- Minimize opportunities for cross contamination by excluding animals from the composting system.
- For a static aerated pile system or an in-vessel method, maintain a temperature between 131 to 170 degrees F for a minimum of three days.
- For a windrow system, maintain a temperature between 131 and 170 degrees F for a minimum of 15 days.
- Again, incorporate.
Record Keeping
Keep records of which field received manure, including rates and dates of application. This is considered just good farm management as well as a part of proper manure management.
Practices to avoid
Manure teas are not acceptable for use on crops intended for human consumption. Sidedressing with untreated manure is also to be avoided. Allowing runoff from manure piles or compost systems to leak to fields.
Remember that manure is not just from cattle, chickens and pigs. Dogs, cats, deer, birds, rodents and flies (Flies are particularly noted for E. coli contamination.) can all potentially be sources of microbial contamination. We recommend that you consider your practices for minimizing the potential for contamination from all animal and insect sources.
If you source manure or composted manure from another source, make it your business to know their practices and that they adhere to GAPs for handling manure and compost. Again, strive for minimizing the risk, since elimination is not a reasonable expectation.
Contact for Indiana and Ohio farmers
Indiana and Ohio fruit and vegetable producers interested in help with manure management practices can contact us at the Ohio and Indiana Specialty Crop Food Safety Initiative. Call Mid American Ag and Hort Services at 614-246-8286 or email maahs@ofbf.org. We are funded by the United States Department of Agriculture's Risk Management Agency to provide free materials regarding GAPs, as well as free on-farm consultations through September 2006. Visit us at the MAAHS website at www.midamservices.org and select “Projects” from the list on the left side of the page.
Organic powdery mildew management
Margaret Tuttle McGrath
Department of Plant Pathology
Cornell University
(Editor’s note: This article was first published by IPM News at Cornell University.)
Powdery mildew is the most common disease of cucurbit crops occurring every year throughout the United States. The characteristic white, powdery fungal growth is readily recognizable on leaves and vines. This growth is mostly spores that are easily dispersed by wind. Symptoms can be difficult to see on watermelon, however, as spores are produced less abundantly than on other cucurbits.
Uncontrolled powdery mildew indirectly affects yield because infected leaves usually wither and die. Premature loss of leaves can result in reduced market quality because fruit become sunburnt, have poor color, or have low sugar content due to ripening prematurely or incompletely. Fruit with low sugars have poor flavor and poor storability. Handles on pumpkin fruit may be shriveled or rotten in addition to fruit being paler orange. Size or number of fruit can be reduced in summer squash and other crops when powdery mildew is severe. Severe disease can also lead to imperfections on fruit rind such as speckling and oedema. In addition, powdery mildew infection predisposes plants to other diseases, in particular, gummy stem blight (aka black rot).
Powdery mildew can be managed with resistant varieties and regular foliar applications of disease control products and fungicides. (Note: In the United States, products for which the manufacturer claims disease control must be registered as fungicides with EPA unless the ingredients are ‘generally recognized as safe’ [GRAS] by EPA.) It is not possible to escape infection because the pathogen produces many wind-dispersed spores, cucurbit crops are grown widely, and conditions often are favorable for this disease. The powdery mildew fungus tolerates a wide range of temperatures below about 100° F and it does not need a period of free moisture on leaves to infect, in contrast with other foliar fungal pathogens. Rain is actually unfavorable. There are now varieties of most cucurbits types with genetic resistance to powdery mildew. Tables of varieties are at http://vegetablemdonline.ppath.cornell.edu/Tables/TableList.htm. Unfortunately it can be challenging to find organically-produced or non-pesticide-treated seed. Some seed companies with only treated seed listed in the catalogue are willing to obtain non-treated seed when available for large orders or regular customers.
Races of the powdery mildew fungus have been differentiated on cantaloupe. With race-specific resistance, it is important to know what races of the pathogen are likely to be present before selecting a variety. If a race is present that the variety does not have resistance for, it may become as severely infected as a susceptible variety. Both race 1 and 2 have been present recently on Long Island, NY. Resistant varieties of cantaloupe and also cucumber can exhibit high levels of resistance with very few symptoms developing.
Disease onset is delayed or development slowed in resistant squash and pumpkin. However, these varieties can become severely infected by the end of the season. Varieties with resistance from both parents (homozygous) usually develop less powdery mildew than those with resistance from one parent (heterozygous). In catalogues these are often described as resistant and tolerant, respectively. Ensure the variety is homozygous before purchasing seed by asking the salesman or checking the on-line variety tables mentioned above.
The powdery mildew fungus has the potential to evolve such that it can overcome genetic resistance. Selection pressure for new strains will increase as resistant varieties are grown more extensively; therefore, an integrated program with a few foliar fungicide applications is recommended to thwart selection of new races of the pathogen able to overcome the resistant variety as well as to improve control in squash and pumpkin. Watermelon was considered naturally immune, but recently crops have been affected, often severely, from Texas to New England, indicating development of a new pathogen strain. Considering how few major genes for resistance are presently in crops (just one in squash and pumpkin), and the pathogen’s proven ability to evolve new races able to attack resistant melon varieties and new strains able to tolerate fungicides, it is prudent to use an integrated management program to preserve effectiveness of resistant varieties.
The fungus causing powdery mildew fortunately is sensitive to many types of chemicals that are approved for organic production. These include oil (mineral and botanical types), sulfur, copper, potassium bicarbonate, and biofungicides (Table 1). Efficacy and cost vary widely. Few products are labeled for other diseases. For effective control, applications need to be started very early in disease development and repeated every 7 to 10 days (14 days with resistant varieties). Established powdery mildew cannot be controlled, not even with systemic conventional fungicides.
Routine scouting is needed to ensure applications are started very early in powdery mildew development. Plants are susceptible to powdery mildew when in their reproductive phase and at any age when grown under greenhouse conditions. Sometimes symptoms begin to develop on field-grown plants before they begin producing fruit, especially when severely stressed due to delayed transplanting or surrounded by tall weeds; removing these stresses can halt powdery mildew development thereby avoiding the need to start applications early. Inspect plants weekly. When first fruit start to enlarge is an especially important time. The scouting protocol entails weekly examining both leaf surfaces of 5 old, crown leaves in at least 10 locations through out a field. Symptoms develop first on older leaves, often on the underside. It is time to start applications when powdery mildew is found at a very low level on at least 1 of the 50 leaves. Once symptoms are easily seen without hunting, potential to effectively manage powdery mildew with rescue treatments is greatly diminished.
The pathogen develops best on the lower surface (underside) of leaves, thus a successful management program necessitates controlling the pathogen on the lower as well as the upper surface to avoid premature death of leaves. Unfortunately there are no products with systemic activity approved for organic production and it is difficult to directly deliver fungicide to the lower leaf surface, even with new nozzle types and air assist sprayers. Foliar applications of sulfur have been more effective than most other organic products for powdery mildew on lower surfaces when compared in fungicide efficacy experiments, apparently because when deposited on the upper leaf surface, sulfur can volatilize and be redistributed to the lower surface. Sulfur is also less expensive than other materials. Like copper, sulfur is an element and thus cannot be degraded and removed from the environment as can materials such as oils. Sulfur is a micronutrient for plants. Note that sulfur can be phytotoxic on melons, especially if applied when temperatures are hot.
All products listed in Table 1, except MilStop, have been evaluated in replicated experiments conducted since 1997 in Riverhead, NY, and found to be effective for powdery mildew. All are considered protectants since they do not move into plant tissue. Product efficacy for providing full-season control ranged from poor to at least as good as the popular conventional protectant fungicide chlorothalonil formulated as Bravo. The most effective products were Microthiol Disperss and Eco E-Rase. GC-3 organic fungicide, Organocide, JMS Stylet-oil (organic formulation), and Champion were also highly effective. No experiment included all products thus they cannot be ranked. Tables of these experiment results will be posted on line at: http://vegetablemdonline.ppath.cornell.edu/.
In summary, to ensure good yield of high quality fruit of cucurbit crops, manage powdery mildew by selecting varieties with resistance, examining foliage weekly to detect when this disease begins to develop, and applying control products to foliage beginning very early in disease development.
Please Note: Organic growers should ask their certifier about product acceptability for their operation before purchasing. The specific directions on fungicide labels must be adhered to -- they supersede these recommendations if there is a conflict. Any reference to commercial products, trade or brand names is for information only; no endorsement is intended.
Table 1. Biocompatible products evaluated for managing powdery mildew, active ingredient, whether exempt from tolerance and EPA registration as a fungicide, labeled diseases and insect pests, and company. Note that a few are not yet OMRI listed. A few products are not labeled for use for powdery mildew on cucurbits (target pest must be specified on the label to be used in NY).
- Bugitol. 0.42% capsaicin and related capsaicinoids, 3.7% allyl isothiocyanate. Kills and repels numerous insects, no diseases on label. Champon Millennium Chemicals. $28.56 at 96 fl oz/A. Not OMRI approved yet. EPA Reg No. 61966-4. Not registered in NY.
- Eco E-rase. 97.50% jojoba oil. Controls powdery mildew and white fly. Labeled presently for use on grape and ornamental crops. IJO Products. $16.25 at 0.5% applied at 50 gpa. OMRI listed. Exempt from tolerance. EPA Reg No. 68186-1.
- GC-3 Organic fungicide. 30% cottonseed oil, 30% corn oil, 23% garlic extract. Controls powdery mildew. JH Biotech, Inc. $23.75 at 1% applied at 50 gpa. OMRI listed. Exempt from EPA registration.
- Organocide. Active ingredient=5% sesame oil; inerts = 92% fish oil + 3% emulsifiers. Labeled for several diseases and insects. Organic Laboratories, Inc. $47.50 at 2 oz/gal. OMRI listed. Exempt from EPA registration.
- Sporan. 17.6% rosemary oil; Other ingredient = 82.4% wintergreen oil. Labeled for several fungal diseases. EcoSmart Technologies. $29.25 at 1.5 qt/A. OMRI listed. Exempt from EPA registration.
- Trilogy. 70% clarified hydrophopic extract of neem oil. Labeled for several diseases and insects. OMRI listed. Certis USA L.L.C. $12.00 at 1% applied at 50 gpa. EPA Reg No. 70051-2. Registered in NY.
- Milsana. 5% ethanolic extract of Reynoutria sachalinensis (giant knotweed). Boosts plants’ natural defense mechanisms; certain fungal and bacterial diseases. Label recently expanded from just ornamental greenhouse crops to include use in field on food crops. KHH BioSci, Inc. $8.75 at 2 qt/100 gal applied at 50 gpa. EPA Reg No. 72179-2. Not registered in NY.
- Prev-Am. 0.99% sodium tetraborohydrate decahydrate. Labeled for several diseases and insect pests in addition to powdery and downy mildew in cucurbits. ORO Agri, Inc. $11-27.50 at 0.4-1% applied at 50 gpa. EPA Reg No. 72662-3. Registered in NY.
- AgriLife. 5% citric acid. Natural plant immune booster. Broadly labeled for fungi and insects. Biological Solutions, LLC. $30-60 at 0.5-1% applied at 50 gpa. Exempt from EPA registration.
- JMS Stylet-oil, organic formulation (note that there is another formulation). 97.1% paraffinic oil. JMS Flower Farms, Inc. $7.43 at 5 qt/100 gal applied at 50 gpa. OMRI listed formulation. EPA Reg No. 65564-1. Registered in NY.
- Serenade. Bacillus subtilis. Labeled for several diseases. OMRI listed. AgraQuest. EPA Reg No.69592-11. Registered in NY.
- Sonata. Bacillus pumilus. Labeled for several diseases. OMRI listed. AgraQuest. EPA Reg No. 69592-13. Registered in NY.
- OxiDate. 27% hydrogen dioxide. Labeled for several diseases. OMRI listed. BioSafe Systems. $21.58 at 128 fl oz/100 gal. EPA Reg No. 70299-2. Registered in NY.
- Armicarb. 85% potassium bicarbonate. Labeled for powdery mildew and other diseases. Helena Chemical Company. $12.69-16.92 at 1.5-2 lb/A. EPA Reg No.5905-541. Registered in NY.
- Kaligreen. 82% potassium bicarbonate. Labeled for powdery mildew. $21.41 at 4 lb/A. OMRI listed. AgBio, Inc. EPA Reg No. 70231-1. Registered in NY.
- Milstop. 85% potassium bicarbonate. Labeled for several diseases. BioWorks, Inc. EPA Reg No. 70870-1-68539. Registered in NY for use on nursery crops.
- Nutrol. potassium dihydrogen phosphate (0-50-32). Labeled for powdery mildew. $11.36-17.04 at 8-12 lb/A. Not OMRI listed. LidoChem, Inc. EPA Reg No. 70644-1. Registered in NY.
- Champion. 77% copper hydroxide. Labeled for several diseases. OMRI listed. NuFarm Americas Inc. $5.70/A at 2 lb/A. EPA Reg No. 55146-1. Registered in NY.
- Microthiol Disperss. 80% sulfur. Labeled for powdery mildew. Will be OMRI listed soon; other sulfur products OMRI listed. Cerexagri. $2.64/A at 4 lb/A. EPA Reg No. 4581-373. Registered in NY.
The stone fruit disease plum pox was confirmed for the first time in Michigan in July 2006. Plum pox was first found in North America in Pennsylvania in fall of 1999. The USDA launched an extensive survey and eradication effort that eventually stretched over three counties. Plum pox was discovered in eastern Ontario and Nova Scotia in 2000, and western New York in early July 2006. PPV has apparently been eradicated from Nova Scotia. The USDA has pursued a vigorous policy of detection and eradication in the United States.
The Michigan Department of Agriculture (MDA) has participated in a national surveillance program for plum pox virus (PPV) since 2000. The discovery of PPV in southwestern Michigan last month was the result of this ongoing survey. The USDA's Animal Plant Health Inspection Service (APHIS) is also involved in the detection effort and determining the spread of plum pox in the United States.
The Michigan Department of Agriculture and Michigan State University (MSU) have announced aggressive efforts to manage the plum pox virus (PPV), known to infect certain stone fruits, such as peaches, nectarines, apricots and plums. The strain identified is not known to affect cherry trees. PPV poses no human or animal health threat.
To read more about the plum pox virus and plans to stop the spread, visit: http://ipm.msu.edu/plumpox.htm
Indiana
Southeast Indiana—Gary Reding
We have had two weeks of perfect weather to fill ears and pods on the popcorn and soybeans. Pollination looks to have been quite good and the ears are filling nicely. The soybeans are about 40-inches tall and podded heavily. I believe these could be some of the best soybeans we’ve ever raised. Rain has been very timely and in perfect amounts as needed.
The past two weeks have been busy with pulling pigweeds out of the soybean crop. That seems to be the main weed we have run into this year and not too bad of a population. I am just trying to get them before they reseed. While walking the fields, we have noticed a lot of beneficial insects keeping the Japanese and Mexican beetle populations to a minimum. There are very few holes in any bean leaves.
In the next two weeks we will continue the grazing of our pastures, working some compost and mowing buffers. We may bale a little hay as well.
Questions
I have attached a photo of a wasp that has been preying on the beetles. If anyone knows the name of it, I would like to know.
Illinois
Southwest Central Illinois—Floyd Johnson
Well it finally rained here last week. We got around two to three or four inches. It is really nice to see green grass again. Currently I am mowing weeds, catching up on books and trying to figure out what to do with soybeans. We had a field day and a neighbor, Dave Perring, brought over a corn tassel cutter to use to top weeds in soybeans. I was looking forward to it, but the engine is just too tough to keep running. Needs a carb kit or something. In the next two weeks I’ll be mowing ditches and stubble ground, plowing some stubble ground and finish paying bills. Also will cultivate soybeans (maybe it’s too late, not sure it would help). Attached are some pictures of grass we have had troubles with.
West Central Illinois—Anne Patterson
We had a very dry summer, but we’ve had 1.7 inches of rain in the past two weeks. Things are green with the best crop of tomatoes I have ever grown. The third planting of green and purple beans is beautiful right now. The flowers and herbs are looking great. The one bust has been with my eggplants, which had extreme damage from flea beetles due to weakened plants from too dry, hot and humid growing conditions. Today it is in the low 80s and sunny—truly a perfect day to be in this business.
Currently I’m deadheading herbs and flowers along with weeding new zinnia flowerbeds. I’m cleaning out beds to add new compost and getting ready to plant Asian greens, lettuce, mesclun, arugula, carrots, beets and kohlrabi for fall and early winter harvest. Continue to harvest: herbs, flowers, tomatoes, tomatillos, squash, beets, carrots, eggplant, pears, peppers, potatoes, cucumbers and beans. The second crop of cukes and summer squash is blooming so I will remove the cover cloth, which was placed to deter cucumber beetles.
The “Country” bouquets are selling well and are a nice change of pace for me. These are a mix of zinnias, anemones, lilies, cosmos and any blooming prairie flowers from my seven acres of prairie and blooming herbs, i.e. Mexican sage, purple basil & anise hyssop.
This week I need to pick the last of the tomatoes in the hoophouse and close it up for at least three weeks to clear out any bugs and give it a rest before I plant in mid-September for winter greens, lettuce and spinach. The recent rains have caused an increase in weeds for late in the season. My part-time worker left after the high heat and humidity during the last week of July and I’ve decided to finish the season on my own. In the next couple of weeks I’ll keep things mowed and continue harvesting. Also will plant winter cover crops by mid-September.
Questions
Does anyone use the portable hoophouse system – i.e. Eliot Coleman? What about low hoops in the field during winter?
West Suburban Chicago—Steve Tiwald
Recently we’ve been experiencing 80-85 degree temperatures and dry conditions with an early morning fog. This year our farming has been more affected by the weather more than any other year we can remember. The temperatures have been so variable. We essentially made no money on our squash. Tomato production appears to be about half of a typical year, even with the tomatoes grown in the greenhouse. One variety looks to produce about one-half pound per plant instead of 10-12 pounds. Of all our tomato varieties, only Carolina Gold is producing good yields.
Other problems we experienced this year due to weather were:
1. Hot and cold cycles had cool and hot season weeds germinating over a longer season causing us to do more weeding on salad greens.
2. Did not get quite hot enough long enough to put up shade cloths over salad greens areas, yet was hot enough to disrupt seed germination and cause excess disease from watering new plantings.
3. Corn germination was very spotty even with multiple plantings.
4. Dandelion greens bolted early and essentially did not make a crop or pay for themselves.
Another area these strange temperature shifts have affected is fruit ripening. Different fruits are ripening two to three weeks late or early or right on time: keeps things a bit confusing.
There have been a few benefits or crops that have done well:
1. Outside or non-greenhouse plantings of basil have grown well this year keeping a nice, deep green color.
2. There have been fewer pests to deal with.
3. Kale has continued to throw nine- to 12-inch leaves all summer due to overall cooler temperatures.
Due to these and some other problems we are experiencing, this is the worst growing season we’ve had in five to six years.
We have large areas tilled and leveled for germinating weeds for a large salad greens planting to run into the cooler fall conditions when growth is slowed down. Harvesting is down right now with little salad greens production. Tomatoes are just now starting to come on with any quantity at all. We are killing what is left of the squash plantings. We are harvesting and processing early Asian pears and mid-season apple varieties. Our fall cabbage and broccoli crop failed due to poor seed germination, both in the field and in seed trays and the planting window is past. This was due to several weeks of hot temperatures.
If we can get the fall salad greens crops in and hold them with a variety of row covers and in the greenhouses, then we can try and salvage the year. We are hoping for a long and mild fall/early winter. Our main activity now is preparing for that. So far we are experiencing a lot of weeds in our late summer early fall plantings.
We have also been working some new accounts in a nearby town selling some of our more dependable and best money-making crops. While this is profitable, it is really about setting things up for next year, getting all the systems and accounts etc. down. We are wrapping up that market expansion over the next two weeks.
We have some apples and Asian pears ripening that need to be picked, sorted and sold.
Northern Illinois—Dave Campbell
It continues to be very dry, although crops look fairly decent at this time. New alfalfa/grass seeding isn’t growing much, due to the dry weather we’ve had for the past seven weeks or so. We plan to bale hay today, and we’re still working on hand cutting weeds out of soybeans. In the next two weeks we will continue cutting weeds out of soybeans, maintain equipment and mow around field borders.
Michigan
Southwest Michigan—Matt Wiley
No weather problems. Best growing season I have ever witnessed. One inch of rain last Thursday (August 17). We just harvested green snap beans and got 3.5 tons/A. Now we are working up soil and getting ready to plant spelt. In the next two weeks we’ll be planting cover crops (oats and radishes).
Northwest Iowa – Paul Mugge
It was extremely hot and dry until the first of August, since then we have received about seven inches. It was in time for the beans and they look great. The corn didn’t pollinate perfectly, but it should be a respectable crop. The problem is with the flax. About half of it was combined prior to the rain and it worked very well in spite of the weeds, although the yield is only about two-thirds of last year. Since then, when it wasn’t raining, the humidity was so high that it wouldn’t dry under the windrows. I finally combined the last three acres on Aug. 22, but it was not acceptable for processing (free fatty acids were too high). It should be okay for feed, however. Currently I am hauling manure to the compost pile and trying to keep up mowing lawn.
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