You can manage your garden for purple martins and tomato diseases

Richard Bogren, Gill, Daniel J.

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For Release On Or After 05/08/09

You can manage your garden for purple martins and tomato diseases

By Dan Gill
LSU AgCenter Horticulturist

Most years I get a few questions asking why purple martins failed to take up residence in a birdhouse provided for them. Purple martins prefer to nest around people, and we like that since they eat lots of insects. Martins are even sociable with each other – purple martin birdhouses are typically built to house a number of families.

So, what’s the problem when you put out a house and the martins decline the invitation? The following are 10 common mistakes to avoid, as compiled by ornithologist James R. Hill III of the Purple Martin Conservation Association.

1. House is too close to tall trees or in yards that are too enclosed. Air space at house height should be void of trees in at least a couple of directions for 40 to 60 feet.

2. Gardener allows other birds to claim the housing first. If the house was not used by breeding martins last year, they will be easily repelled from the entire housing complex if other birds arrive first. On the other hand, they seldom are intimidated from reoccupying the site they used the preceding year.

3. House is too far from human housing. Martins prefer to nest within 100 feet of people, where they have learned they are safer from predators (snakes, raccoons, opossums, hawks, crows, owls). The house should be in the center of the most open spot available, 30 to 100 feet from human housing.

4. House is not painted white. White reflects the sun’s heat, highlights the dark entrance holes and best enhances the male’s courtship display.

5. House is opened up too early. Purple martins migrate, returning to our area by February or early March. The oldest arrive first and return to where they bred the preceding year. Last year’s fledglings show up over the following 12 to 16 weeks, beginning 4 to 5 weeks after the “scouts.”

6. Failure to open the martin housing early enough. This sounds like a “Catch 22,” considering the preceding point. At unestablished sites, the birds have to see either the open entrance holes or other martins there. On the other hand, if breeding birds were there last year, gardeners can wait until they see martins standing on the house to open it up. Purple martins will return to the same breeding site year after year.

7. Allowing vines or shrubs to grow up under the house. Purple martins tend to avoid such unestablished sites because they are more accessible to predators.

8. House is not built to specifications. A compartment’s floor dimensions must measure at least 6 inches by 6 inches, and 7 inches by 12 inches is far superior. The entrance hole should be about 1 inch above the floor and be 2 inches to 2 1/4 inches in diameter.

9. House is attached to, or too close to, wires. Martins know instinctively that squirrels can gain access to the house.

10. House that cannot easily be lowered and cleaned. Gardeners need to lower the houses often to evict nest-site competitors and check on martin nestlings. Any such disturbances will not cause martins to leave their nest or site.

Many diseases plague tomatoes

We have more than our share of diseases that attack both the tomato plant and the fruit.

Buckeye rot attacks the lowest tomatoes first. Bruised-looking areas appear on the fruit and rapidly enlarge. Promptly harvest and dispose of infected fruit. Make sure plants are mulched to prevent the fungus from splashing up from the soil onto the lower fruit. If needed, apply the fungicide chlorothalonil to minimize damage.

Blossom end rot forms a dark, dry, leathery area at the bottom of the fruit. This disease is caused by a calcium deficiency in the fruit. Blossom end rot can be controlled by maintaining an even supply of soil moisture (be sure to mulch) and by applying calcium if needed. Blossom end rot sprays that provide available calcium are also available and can be applied to developing fruit to prevent the condition.

Early blight is a fungus disease that can affect both leaves and stems of tomato plants. Symptoms of the disease are brown spots on stems or leaves, which eventually turn yellow (usually starting on the lowest leaves). Preventive sprays at regular intervals are necessary to control early blight.

Fusarium wilt is the most common and destructive soil-borne disease in Louisiana. The fungus enters the plant through the roots and develops inside the stem. Plants show a progressive yellowing and wilting, starting at the bottom. Two weeks may elapse between the first symptoms and plant death. The best control measure for fusarium wilt is to plant tomato varieties that are resistant. Keep in mind that resistance does not imply immunity. Under stress conditions or in heavily infested soils, resistant types also may develop the disease.

A number of useful fungicides, both organic and synthetic, are available for dealing with disease problems in tomatoes. Used promptly and according to directions, they can help save a crop. Contact your local LSU AgCenter extension office for help with diagnosis and control recommendations.


Rick Bogren

4/27/2009 8:08:01 PM
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