Lauterbach: Water works fine for blasting aphids; pollination tricky without honeybees

Special to the Idaho StatesmanJuly 12, 2013 

Don’t have these around? You might have to take on the task yourself.

MCT

If your shrubs or trees are full of aphids, please don't use toxic sprays on them.

Just use a trigger nozzle on your hose and blast them off with water. A water jet will also displace bees and other beneficial insects, but they can recover and fly away. Most aphids can't fly, and will die on the ground.

Boiseans have been reporting a lack of honeybees this year. Too many folks are still actively poisoning them, unintentionally, I hope. That year-round systemic insecticide available for shrubs and trees will kill bees.

Without bees, we'll just have to depend on alternative pollinators who may or may not pollinate our crops. Butterflies, bumblebees and other variations of bees, wasps, grasshoppers, houseflies, and other flying insects do some pollinating, but they're not as efficient as honeybees. Only the Osmia mason bees are more efficient, and they mainly pollinate tree fruit.

If you want food such as squash, you may have to pollinate it yourself. Here's how: In the evening, find male and female buds that show bits of flower color along seams. Use masking tape to hold a male and a female flowerbud closed. Male flowerbuds are at the end of pencil-thick stalks. Female buds sprout from miniature versions of the squash that will be produced after pollination.

Next morning, untape the male bud, and wait for the flower to open. Remove all petals. Don't set what's left of the male flower down, or you'll lose some pollen. Hold the stem in your teeth while you untape the female flower. After it opens, daub the female parts of the flower with the male flower, then re-tape the female flower shut to prevent accidental cross-pollination by an alternate pollinator.

If your summer squash has both male and female flowers open and small squashes appear, and soon the end turns soft and the squash obviously dies, that's due to a lack of pollination or insufficient pollination. Cucumbers may show that effect, too.

Many vegetable garden plants have "perfect" flowers, containing male and female reproductive parts. Even so, some plants are self-sterile. I believe Physalis (tomatilloes, cape gooseberries, and ground cherries, for example) is self-sterile. Often, when you plant just one tomatillo, no fruit develops. 'm experimenting this summer with one purple tomatillo and one giant green one. So far, lots of blossoms, no fruit set.

To develop a fruit, pollen must be transferred from the male anthers to the stigma, which then transfers the pollen to the flower's ovary.

Some movement of a perfect flower is required for this transfer, sometimes wind alone will do. This is fairly easily accomplished with perfect flowers, more difficult when you have male trees to pollinate female trees, for instance.

Tomatoes, chiles (peppers), beans and eggplant are some examples of perfect flowers. Theoretically, a tickling breeze should transmit pollen, sparking fruit set. Actually fruit set is enhanced by visits from insects, especially those such as bumblebees that sonicate, or buzz the flowers. In some greenhouse situations, growers sonicate their flowering plants with electric toothbrushes.

You may have heard that neither tomatoes nor peppers will set fruit above 90 or below 55 degrees. We've had some scorching heat, but remember, nights have been in the 60s and 70s, not too cool for fruit set, and daytime temperatures don't get above 90 until noon or later. There is a window of several hours that pollen can be viable, so we do have some fruit set.

Send garden questions to melauter@earthlink.net or Gardening, The Statesman, P.O. Box 40, Boise, ID 83707.

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