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Home  > Question of the Week

Question of the Week

Permalink I am starting an organic peach orchard. What are the disease and pest concerns associated with growing peaches? Is it acceptable to paint the trunk with white latex paint mixed with copper sulfate to prevent fungus from infecting the tree?

Answer: All the answers you are looking for are contained in the ATTRA publication Peaches: Organic and Low-Spray Production, available at This publication covers all major (and most of the minor) pests and diseases of peaches and their control using organic methods. Geographic location and climate play a particular role in the incidence and severity of peach diseases and pests. Commercial scale production of organic peaches in the eastern U.S. is very, very difficult; in fact, it is virtually non-existent. As you read the entire publication and pay special attention to a couple of add-ons at the end of the publication, "Postscript: The Peach Problem and Local Food" and "Appendix I: Hypothetical Pest-Control Calendar for an Eastern Organic Grower."

Regarding the "Hypothetical Pest-Control Calendar for an Eastern Organic Grower," note that a cost analysis of such a program was not included. For this there are a number of reasons but, suffice it to say, it would almost certainly be considerably expensive given the usual high cost for some organic pest and disease controls. You would almost certainly have to get an organic premium for the fruit in order to recoup the costs of production.

Another thing to pay special attention to in the publication is post-harvest control of brown rot (and other rots) on the fruit. Currently, this is difficult for organic peach growers in the West, but it would be of paramount importance to someone in the East where disease pressure is more intense. Perhaps the most important post-harvest factor for an organic peach grower to consider is speed; i.e., get peaches cooled down and to market as quickly as possible after harvest.

Latex paint is not allowed in certified organic production because it is considered "synthetic." Copper fungicides, in general, are allowed in organic production but be sure to check with your certifying agent to find out which formulations and brands are registered for organic production. Not all are. I'm not positive which disease you're trying to control on the trunks with paint and copper, but I'm relatively certain you're talking about bacterial canker. The evidence for control of bacterial canker with copper is mixed, some studies indicating that it is only of minor or no help. The white paint is used to reflect the winter sun shining on the south and southwest facing parts of the trunk; otherwise, the winter sun warms up those sides and then subsequent freezing can cause bark cracking, which then becomes the infection site for the causal organism, Pseudomonas syringae. The best organic alternative I would recommend is homemade whitewash (see for an online recipe). Do not use any paint with petroleum distillates (e.g., paint thinner, kerosene) as it can penetrate the bark and kill live plant tissues.

Finally, I'd like to urge some general caution. One of the foundational strategies for disease and pest control in annual crops is crop rotation, something that you can't do with perennial fruit crops. Indeed, a disease like brown rot builds up in the orchard if you're not extremely careful, and you can't rotate out of it. On the other hand, peaches are one of the most precocious of the tree fruits, often setting fruit the second year after planting, so you should be able to figure out relatively quickly what you're going to be up against. With peaches, experiment with a small planting first and don't get fooled by the first fruiting year, the so-called "honeymoon year" because it's before the pests and diseases have found the peaches and settled in.

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Permalink Can dung beetles help my pasture ecosystem? What are the signs that they are present and how can I encourage populations throughout my pastures?

Answer: Dung beetles belong to the zoological order Coleoptera and family Scarabaeidae and there are over 90 species in the United States. Dung Beetles can help improve your pasture system in several ways. They play a small but remarkable role in the pasture ecosystem. They feed on manure, use it to provide housing and food for their young, and improve nutrient cycling, soil structure, and forage growth in the meantime. Dung beetles are important enough in manure and nutrient recycling that they well deserve the pasture manager’s attention.

Dung beetle benefits to livestock and the pasture environment just might outweigh their somewhat disgusting choice of food. For example, manure is the breeding ground and incubator for horn flies and face flies, two economically important pests of cattle. As dung beetles feed, they compete with the fly larvae for food and physically damage the flies’ eggs. Fly populations have been shown to decrease significantly in areas with dung beetle activity.

Dung beetles are also reported to be effective biological control agents for gastrointestinal parasites of livestock. The eggs of most gastrointestinal parasites pass out in the feces of the host. The eggs then hatch into free-living larvae and develop into the infective stage. They then migrate onto grass, where they can be ingested by grazing animals, and complete their life cycle within the animal. If the manure/egg incubator is removed by beetles, the eggs perish and the life cycle of the parasite is broken.

On a pasture-management level, dung pat removal is beneficial for forage availability. Most ruminants will not graze closely to their own species’ manure pats. Research has shown that the forage is palatable but avoided because of the dung pile. Consequently, cattle manure deposits can make from 5% to 10% per acre per year unavailable. By completely and quickly removing the manure, dung beetles can significantly enhance grazing efficiency.

The tunneling behavior of dung beetles increases the soil’s capacity to absorb and hold water, and their dung-handling activities enhance soil nutrient cycling. An adequate population and mix of species can remove a complete dung pile from the surface within 24 hours.

There are several things you can do as a producer to encourage the presence of Dung Beetles. Dung beetle larvae are susceptible to some insecticides used for fly and internal parasite control for cattle, especially Ivermectin. Discontinuing the use of this type of insecticide will help increase your population of dung beetles. Backrubbers, ear tags, and the occasional use of insecticide dusts and sprays are alternatives that have little or no effect on dung beetles. Another option is to treat cattle during the coolest months of the year, as the beetles and larvae are inactive at those times. Better yet, before treating your animals for internal parasites, take a fecal sample to your veterinarian. An egg count can help determine parasite load and whether the symptoms you may be seeing in the form of low gains, weight loss, unthriftiness, etc., are truly being caused by parasites.

Controlled grazing systems increase dung beetle populations and varieties by concentrating the manure in smaller areas, thus reducing the time beetles must spend in search of food. Watch the length of time it takes for the manure pats to disappear in your pasture. If they remain intact for more than a few days, chances are your dung beetle population is low to non-existent. Look for hole formation in the surface of the manure pats. Many types of beetle and other insects also help to desiccate the pats. Management is the key to increasing the number and variety of dung beetles and other beneficial insects.

For more information on the benefits of dung beetles and pasture management, refer to ATTRA publication Dung Beetle Benefits in the Pasture Ecosystem at

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Permalink I am interested in micro-hydro on my farm. What do I need to know?

Answer: Farm hydropower projects have existed for many years, from waterwheels used for grinding grain and forging to modern hydroelectric turbines designed to run compressors and motors. Micro-hydro systems — those that produce less than 100 kilowatts of electricity — can offer a sustainable and continuous source of renewable energy on farms. It is one of the most reliable and consistent sources of renewable energy available. A good water resource with a year-round flow and several feet of elevation drop can provide years of continuous power.

Farms often have easy access to lakes and ponds as well as naturally occurring streams and rivers. When farmers possess the rights to use the water resources that are contained on-farm, they usually face fewer obstacles both in permitting and in the efficient use of farm-scale hydropower. Hydropower can be a continuous source of energy as long as enough water is flowing.

To determine the hydropower potential of the water flowing from your spring or in your stream, you must know both the flow rate of the water and the head. The flow rate is the quantity of water flowing past a point during a given period of time. The flow rates of micro-hydro systems are typically measured in gallons per minute or cubic feet per minute. The head is the vertical drop measured in feet from the headwater (in the case of a dam) or the point where the water enters the pipeline (if no dam exists) to the point where the water leaves the turbine housing. With some turbines, such as those that use a "draft tube," head extends to the base of the tube.

Micro-hydro systems generally consist of the following components:
• A trash rack, weir, and forebay to prevent debris from entering the pipeline and turbine
• A pipeline (also called a penstock) to pipe water to the turbine
• A powerhouse that contains the turbine and electronics
• A water turbine that converts the kinetic energy of the flowing water into mechanical energy that can be used directly or to drive a generator or other piece of equipment — this is the main component of a micro-hydro system
• A tailrace to release the water back into the source it came from
• Transmission lines to deliver electrical power where it is needed

The environmental impact of micro-hydro systems is usually small but by no means absent altogether. When water is diverted or dammed, or when structures installed in the stream channel interfere with the natural flow of the water, there is an environmental impact. However, compared to large hydropower dams, micro-hydro systems have a smaller footprint and generally lower environmental impacts. Even so, there are several local, state, and federal agencies that may want environmental impacts to be assessed for a micro-hydro project.

Obtaining the necessary permits from local, state, and federal agencies is a key part of any micro-hydro project. Although the permitting process may appear burdensome, it is intended to protect the water resource and its users, including the fish, plants, and animal communities that also use the water. It is best to identify all the necessary permits and approvals to develop a hydro resource very early on in the process. Doing so will help you avoid wasting time in planning your micro-hydro project.

Any analysis of the economics of a micro-hydro system should include both the initial investment costs and the operation and maintenance costs. The initial investment cost calculation must include not only the turbine and generator, but also other variable expenses such as any pipes, power lines, buildings, dam construction, civil engineering work, permits, and legal work. One characteristic of many micro-hydro systems is that the up-front costs can be high, although the up-front and operating costs may be very competitive with generators, wind-electric systems, and solar-electric systems, as well as with conventional energy sources. Except for small maintenance costs, a micro-hydro system should provide "free" energy for 20 to 25 years or longer.

For more information on micro-hydro, review the ATTRA publications Micro-Hydro Power: Is It Right for My Farm? and Micro-Hydro Power: A Beginners Guide to Design and Installation. Other ATTRA publications you may find useful include Renewable Energy Opportunities on the Farm and Measuring and Conserving Irrigation Water.

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Permalink What can you tell me about pruning greenhouse tomatoes?

Answer: The type of tomato plant that you are producing can dictate the need for pruning. Determinate varieties often are early and have a short but concentrated production season. These plants are staked or caged but are not adapted to trellising. Determinate varieties are not heavily pruned, regardless of the support system, because most of the fruit is produced on the branches.

Indeterminate varieties continue to grow and produce leaves and flower clusters until disease, insects, cold, or lack of water and fertilizer kills the plants. Indeterminate varieties include Better Boy, Floradel, and Big Beef. Indeterminate varieties are heavily pruned when trellised, moderately pruned when staked, and lightly pruned when caged. The type (whether it is determinate or indeterminate) of tomato should be listed on the seed packet.

Pruning removes small shoots where each leaf joins the stem. Properly pruned plants produce larger and earlier fruit than non-pruned plants of the same variety. Remove shoots when they are less than four inches long to avoid injuring the plant. The larger the sucker before removal, the larger the resulting wound and the more wasted plant energy that went into the sucker. Tomato plants can be injured by pruning too late or too aggressively. The leaves will look stunted and wrinkled, and the injury will set them back a bit.

Remove a sucker by grasping it between your thumb and second finger and bending it to the side until it breaks. This is best done early in the day when plants are crisp and not wilted from the day’s sun and heat. Do not cut suckers with a knife because this is one way to spread virus diseases.

While pruning tomatoes can help with improving ripening times, it can also cause more sun scald damage to fruit that is exposed to the sun. This may not be as important in a cloudy climate, but it is a consideration for sunny locales. Being less vigilant about pruning as the plant starts to fruit might help prevent this.

Johnny’s Selected Seeds has a great video on pruning tomatoes that distinctly shows which shoots to prune and how to leave two leaders on the tomato plant. It is available at

For more information, consult the ATTRA publication Organic Tomato Production. This publication focuses on the specific challenges of tomato production, including site selection (soil and climate), variety selection, sources of organic seeds and organic annual transplants, organic grafting, planting and training/staking arrangements, soil fertility and fertilization, crop rotation, and pest (insect, disease, and weed) management. Harvest and yield/productivity are closely related to marketing possibilities. While market conditions are extremely region-specific, this publication also addresses a few general principles on marketing and economics of organic tomatoes. It is available at

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