Question of the Week
I’m building stalls for sheep and goats. What can I use to treat the wood that won’t be toxic to the animals?
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Answer: Pure linseed oil would be a good choice—it has been used as a wood preservative for centuries. Linseed oil is non-toxic to sheep or horses. In fact, it is sometimes used in sheep and cattle rations as a source of energy and Omega 3 fatty acids. Raw linseed oil has a slower drying time than boiled linseed oil but does not contain synthetic solvents.
Linseed oil soaks in best if you warm it to around 110 degrees Fahrenheit and apply it with the board lying horizontally. Apply it to all sides of the boards, with a heavy coating on the edges. This is where the weathering will affect the board the most.
Raw linseed oil has a slower drying time than boiled linseed oil but does not contain synthetic solvents. Linseed oil treatments may require repeated applications every three or four years. The treated wood can be painted after the linseed oil fully cures.
To learn more, consult the ATTRA publication Pressure Treated Wood: Organic and Natural Alternatives, available at https://attra.ncat.org/attra-pub/summaries/summary.php?pub=73. This publication includes a discussion of currently used materials, lumber treatments using less-toxic materials, decay-resistant lumber species, and an explanation of the National Organic Program Regulations.
I’ve inherited an orchard with four- to five-year-old apple and pear trees that have been suffering fire blight. What can I do?
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Answer: First, break out infected limbs six to eight inches or more below the last visible sign of infection, and remove those infected parts from the orchard area. Do not fertilize any trees with fire blight, as the bacteria favor young, succulent growth. That's about the best you can do right now. But it’s important that you understand as much as possible before taking some action steps.
Fire blight, caused by the bacterium Erwinia amylovora, is the most serious and economically damaging disease of pears and one of the most important of apples. It is particularly troublesome in the humid eastern United States. Infection is triggered by heat and moisture, and can spread rapidly—even within a matter of hours. It can be transmitted by bees, aphids, psylla, or other insects, and can also be spread by blowing wind and rain. Pruning can be another source of infection. Affected branches wither and turn black or brownish black, as if scorched.
Most branch tips, once infected, wilt rapidly, taking on the characteristic shape of a "shepherd's crook." The bacteria gain entry to the tree through blossoms or lush, tender new growth and, once inside, begin to work toward the roots. If the disease spreads unchecked to the trunk and roots, it can kill the tree. Under the bark, the bacteria form a canker where they will survive the winter, only to infect more trees the next year.
Because fire blight development is greatly favored by the presence of young, succulent tissues, cultural practices that favor moderate growth of trees are recommended. These include using only half as much compost as for apples, never using fresh manure, and avoiding heavy populations of clovers and other legumes around the base of the tree. Likewise, heavy pruning can promote lush, vigorous growth, so such pruning should be avoided.
Choosing fire blight-resistant apple and pear cultivars is a good start to managing fire blight, but it is by no means a panacea. Relative resistance to the disease is sometimes informally measured by the extent of visible infection to the age of wood. For instance, the Kieffer pear cultivar is commonly referred to as resistant because the disease rarely proceeds beyond one-year-old wood; you might see a lot of blight on Kieffer in a bad infection year, but rarely will such infection move beyond young wood and threaten the tree’s life. Conversely, a highly-susceptible cultivar, like Bartlett pear or Gala apple, under disease-conducive conditions could incur an infection that could run from new growth to roots and kill a mature tree in a single year. Note that resistance does not equal immunity. "Resistant" cultivars can still get fire blight.
Preventing infection is the next key to fire blight control. Sprays of agricultural-grade antibiotics, applied at early bloom to prevent infection, have been the standard commercial control since the 1950s, but they are scheduled to be phased out for certified organic use in 2014 due to concerns about the build-up of antibiotic-resistant strains of bacteria. University researchers and the pear and apple industries have been diligently working to find viable substitutes to these antibiotics, and their diligence is paying off with the development of several biocontrol products.
In general, these biocontrols work similarly to one another. They are non-pathogenic competitors with E. amylovora, and as such do not directly kill propagules of E. amylovora; rather, they occupy the same
sites that E. amylovora would, provided they get there first. Therefore, in order to be effective, these should be applied to newly-opening flowers (multiple applications will probably be necessary). Since they do not directly challenge the metabolism of E. amylovora, there is little risk of the pathogen building resistance to them.
Once fire blight infection has occurred, there is no spray or other treatment, beyond quickly cutting or breaking out newly infected limbs, that will minimize damage. However, infection has almost certainly extended beyond what the grower sees; therefore, it is all too easy to spread the disease by trying to prune it out during the growing season. If you do cut during the growing season, remove all blighted twigs, branches, and cankers at least eight inches—some sources recommend 12—below the last point of visible infection, and burn them. After each cut, the shears can be sterilized in a strong bleach or Lysol® solution (one part household bleach or Lysol to four parts water) to help avoid transmitting the disease from one branch to another, although there is some disagreement about the effectiveness of disinfection. Lysol is less corrosive than bleach to the metal parts of the pruners. Some have found it more convenient to use a spray can of Lysol disinfectant carried in an apron rather than a plastic holster or glass jar with a liquid solution.
During the winter, when the temperature renders the bacteria inactive, pruning out fire blight-infected wood can proceed without sterilization of pruning tools and need not extend as far below the visible canker.
For more information, consult the ATTRA publication Tree Fruits: Organic Production, available at https://attra.ncat.org/attra-pub/summaries/summary.php?pub=2.
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Answer: There are several possible causes for feather loss:
- Occurs in flocks at least a year old
- Takes several months to complete
- Can be triggered by stress (hot or cold weather, feed, disease)
- Usually occurs once a year (fall)
- Typical molting sequence: head -> neck -> chest -> back -> wings -> backsides and tails
- Level of molting varies year to year, and depending on breed
- Sometimes chickens molt at different times and different ways
- Rooster: If you have a rooster, most likely you’ll see feather loss around the neck and back.
- Active layers need a well balanced ration with adequate protein and energy. Inadequate quantity or quality of protein and energy in the feed can cause feather loss. Make sure you are providing adequate feed for the current stage of production and that all the chickens have access to the feeders.
- Pecking is a bad habit, and it is hard to stop. One possibility is to darken the affected areas with 'blu-kote' or other gentian violet materials (not OMRI approved). This dyes the skin purplish blue, so the hens don't peck (use gloves to apply).
- Pecking may also be due to unbalanced nutrition: more roughage and protein may be needed. Access to oyster shell, as well as greens and other fun things to eat like melons and squash, can also be helpful. Reduce empty calorie treats like cracked corn or stale bread.
- Pecking may be due to boredom/crowding. Make sure there is enough space in the chicken coop and access to feed for everyone.
Parasites (mice, lice and fleas):
- Usually the whole flock is affected
- Lice: look for them at the base of the feathers.
- Mites and fleas: look for them in the barn. White cotton-like substance will show up where they are hiding (barn floors or walls). You can also look for mites on the birds at night.
- Lesions in chickens: scratches and bite like lesions on skin. Look for parasite feces: part feathers and look for “dirt” around belly and tail area.
- If you find parasites in the birds or barn: clean the coop, remove cobwebs, and treat chickens and barns. Clean walls, floors, nest boxes, and the birds themselves. Roosts can be spread with natural oil. Diatomaceous earth in dust baths can also be a treatment.
- Prevent contact with wild birds and rodents (though this can be hard to do on backyard poultry flocks).
Other alternative treatments:
- Spray vent area of birds with a 10% garlic solution in water
- Sulfur solutions (high concentration: >5.3%). Note: Sulfur is 'allowed with restrictions' by OMRI
Additional resources can be found on the Livestock: Poultry section of the ATTRA website, at https://attra.ncat.org/attra-pub/poultry/.
Also see ATTRA's Biorationals Pest Management database at https://attra.ncat.org/attra-pub/biorationals/.
What can you tell me about using weeder geese as a sustainable weed control method in my asparagus field?
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Answer: First, you should positively identify what type of weed species you have in your asparagus patch, as this will affect the effectiveness of weeder geese compared with other methods of weed control. Weeder geese will keep down most species of grasses; however, they will avoid weeds like Curly Dock and goldenrod. If you have quackgrass (a perennial weed), the pruning action by the weeder geese will make it worse. This is because weeder geese graze on the grass tops and leave the root systems relatively untouched. Eating the plant tops encourages root growth in perennial weeds and makes them more difficult to get rid of, and those weed roots will then compete with your asparagus crowns and roots. If you have quackgrass, the best way to get rid of it is to hand-weed it. Weeder geese seek out young tender grasses/weed seedlings rather than large, established plants. This is also something to consider before buying geese, as they will not be effective in managing large, established weeds in your area. You want them to attack the new, young, succulent weed growth as soon as possible.
Another option to help address weeds in your asparagus field is to do a salt burn on them. This is an ancient weed-control strategy that is still in use today. Many people shy away from it because salt can easily burn many types of plants; however, asparagus is very salt-tolerant. We suggest mixing two pounds of table salt in one gallon of warm water and sprinkling it on the weeds. The best time to do this is either before the asparagus sprouts emerge or after you have harvested the asparagus and the ferns are left to grow through the summer months. Although asparagus is a salt-tolerant perennial, it is not recommended to apply the salt water to new growth, as you might burn the tender young shoots as they emerge.
In regards to containment and fencing, weeder geese require a fairly management-intensive grazing setup to be most effective in weeding. If you turn them out on a large area for an extended period of time, they will likely trample small asparagus shoots as they emerge with their big feet and begin to feed on non-weeds (your crops), which is not desirable. That being said, weeder geese do best when allowed to graze in a small, managed area enclosed with temporary fencing. This prevents them from wandering off in search of better, tastier young shoots. It is also highly recommended that you closely watch them to make sure they are not eating your crops.
The stocking rate will vary depending on availability of food. For example, a dozen geese in a few hundred square foot grazing area for a short period of time – say several hours – should be sufficient.
In regards to feeding and nutrition, ideally you want to feed a ration of about 20% grain and 80% from grass/grazing. If you feed your geese too much grain, they will not be motivated to forage and eat the weeds. Additionally, weeder geese are most active foragers before breeding season (spring) and after their young are out of the nest. During breeding season, they will sit tight on their nest most of the time and eat very little while incubating.
Ideally, you want to get your weeder geese as young goslings direct from a hatchery. This will allow you to "imprint" them, which will be helpful in keeping them easy to handle and move, as well as from wandering off. Domestic geese are poor flyers, unlike their wild migratory cousins, and while they way get a few feet off the ground, it is very unlikely they will far enough to fly away. They may see wild geese flying over and get excited and flap their wings, but you don’t have to worry about them taking off to join them. Imprinting should begin as soon as you receive your goslings. This is accomplished by being the only person they see for about their first week of life. This includes you being the only person who feeds and waters them. Keeping young goslings in a brooder will help you accomplish this, which will happen in about five to seven days. After that, they will see you as their mom and stay pretty close.
What is the best process for efficiently transplanting rootstocks and graftlings on a small or medium scale?
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Answer: There are many ways to accomplish this. Some folks will work up the rows really well (using a tractor first to get deep, and then a BCS tiller to pulverize the soil). Then, with a long-faced hand hoe and positioned on their knees, they work their way down the row, transplanting the graftlings about every 12 inches. Getting the soil really loose before starting to transplant is key if you don't like to spend time on your knees. Pulverizing the soil with the BCS tiller is a hard decision—there are worms and other soil life to worry about, so it's best to only till the actual row and not the walking aisles between the rows. That leaves plenty of worms to re-colonize the tilled rows.
Another approach is to have an "up person" with a shovel making holes or slits, and a "down person" putting in the graftlings and covering up the roots. Depending on soil texture and tilth, there are times you could just go through once with a garden fork to loosen up the soil and then follow on your knees and place the graftlings in with the hand hoe. The process can go pretty fast.
Watering in the transplants is always recommended to make sure the soil sifts in around the roots.
Out west in the big nurseries, this process is, for the most part, automated, with two people sitting on the back of a transplanter pulled by a tractor. The tractor opens the ground just in front of the transplanter, and the people put in the rootstocks or graftlings at a pretty fair pace. After the transplants are placed in the slit made by the tractor, a trailing part of the transplanter throws the soil back to the row and tamps it down. You may have seen videos or photos showing something similar in the big strawberry farms out west.
The process does take some experimentation, and there very well might be a better process that will suit your equipment and labor better, so keep an open mind and figure out where you can improve it to suit you.
For more information on tree fruit production, see the ATTRA publication Tree Fruits: Organic Production Overview, available at https://attra.ncat.org/attra-pub/summaries/summary.php?pub=2.