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Thursday, June 2, 2011

Spider Mites Can Be Controlled

Spider Mite Damage But Obviously Not Tomato.
What to look for? Yellow speckling or stipuling,
dusty appearance on the leaves, webbing may or may
not be present.
Q. I am hoping that you can help me, to help my son. He lives in southern California, with a young family. In order to make ends meet, he has created a good size garden for his family, to have fresh vegetables. Some of his tomatoes are getting ready to be harvest, but his crops are being plagued by spider mites. He has released a large amount of lady bugs, from his local nursery, but they don't seem to be solving the problem. Is there something that he can treat his crops with, that will not contaminate the vegetables? Please give me some "fatherly advice" for him.

A. When your son purchases transplants in the future try to find a supplier who is growing them by using only organic pesticides. Some growers will spray transplants with a hard pesticide to knock everything down before shipping them out. This way they get to market looking pristine and with few insect problems.

The problem with this approach is that spider mites are controlled by other insects and predatory spider mites. Once these predators are killed any new infestation of spider mites takes off like a rocket since they reproduce so quickly and their predators are gone.

Spider mite population explosions are enhanced if plants are covered in dust. Wash them periodically, particularly after a wind may have covered the leaves in dust. As far as chemical controls of an organic nature try the use of insecticidal soaps or horticultural oils or perhaps both.

I have heard some recommendations that include the use of Neem oil but people are recommending mixing a soap or detergent with the Neem oil. No, no, no. You must never mix a surfactant or any kind of soap or detergent with oils. This destroys the basic property of an oil that kills insects; namely suffocation. Use both of them, but use them separately or alternate their use.

Insecticidal soaps must be applied every 3 to 4 days or no more often than the label recommends but spray to include the undersides of the leaves for any chemical control to be effective. Never spray in the hot times of the day but only very early in the morning or late at dusk when bees have returned to their homes. Bees will succomb to these sprays. I hope this helps your fatherly advice.

Squash Fails to Fruit Without Active Bees

Summer Squash Failing to Fruit Due to Lack of Pollination. Photo by reader.
Q. I have had great success growing both yellow and green squash in my garden for the past five or six years.  Last month I harvested about ten nice pieces, but in the past couple of weeks they have all been turning very hard and the yellow pieces have turned dark and almost orange.  I have attached a couple of pictures of both the fruit and the plants.  Please let me know if you any suggestions.
A. Your summer squash looks nice. You will get more blemish free fruits with twice to three times a week sprays of insecticidal soaps including spraying the undersides of the leaves. The lack of squash development is due to poor pollination most likely due to cool weather and poor bee activity.

You can attract more bees to the area by planting plants that bees love and flower at the times your vegetable garden needs pollination. Bee loving plants include many of the herbs which are allowed to flower. These might include rosemary, basil, lavender, oregano and thyme to name a few. Woody ornamental plants typically flower for short periods of time but there are some like Texas Ranger, brooms like Scotch broom, lantana, verbena, and others. Go to your nursery and see what is in bloom, particularly reds, purples, pinks and start planting.

Some gardeners like to hand pollinate squash for better setting of fruit or if you want to save seed from certain squash for planting next year. If you want to save seed and you don't prevent contamination from other melons or squash then your seed will not come true. Here is a video on hand pollinating squash and some great background on this family of vegetables.


Monday, May 30, 2011

Deadly Pillbugs Strike Again

Q. I have voracious pill bugs eating my tomato plants (starting at the stalk at ground level).  These are the bugs that resemble armadillos and can roll themselves into a ball.  Is there anything I can do to protect the plants or get rid of the bugs?

Pillbugs. Thanks Texas A and M University!
A. If they roll into a ball then they are considered pillbugs. The pillbugs or sowbugs, even though they do help in the decomposition of dead plants into organic matter, will damage soft fruit and other soft plants. Particularly if there are large numbers.

They like to congregate under boards, cardboard, rocks and other flat surfaces that stay moist and have plenty of air. Sometimes you can lay out boards or cardboard and let them congregate under the surfaces and then scoop them up and get rid of them. You can also put out semi rotten tomatoes or other vegetables which will act like magnets and attract these varmints. Then you can scoop up these rotting fruits and vegetables along with the pillbugs and dispose of them. That won't get rid of them but it will take the numbers down.

You can protect the plants with cardboard collars such as the inside tubes in toilet tissue, spray the soil surface around young plants with pyrethrum or dust with diatomaceous earth.

Apply Insecticidal Soaps Frequently for Effective Control of Garden Insects

To protect vegetable and herb plants from chewing insects you should be spreading with an insecticidal soap every 3 to 4 days. Insecticidal soaps can be purchased or made at home using 2 ½ tablespoons of a liquid detergent such as unscented Ivory liquid, Amway or Dr. Bronners in a gallon of water. However, insecticidal soaps are expressly manufactured for this purpose and are preferred.
Insecticidal Soap
Don’t use liquid detergents with additives such as scents or hand conditioners. This spray must come in contact with the insects. Make sure you spray on the undersides of the leaves and stems where most of the insects party. Any residue left behind does not do very much. Spray when bees are not present and don’t spray plants that are in bloom unless it is at sunrise or sunset since it is also lethal to bees.

Dr Bronners Peppermint Soap

Mulching, Staking and Painting Important to New Fruit Trees in the Hot Desert

Mulch Applied to New Fruit Trees With Growth Difference In One Season
If you planted fruit trees this spring please apply 3 to 4 inches of course wood mulch, not bark mulch, around the trees a distance of 3 to 4 feet from the trunk. You must keep the wood mulch away from the trunk but distance of 6 inches so the trunk does not rot at the base. After the tree is 3 to 4 years old and the trunk is mature with bark you cannot allow the wood mulch to lie against it.

After these very high winds you can see the wisdom in securely staking newly planted trees in our climate. Stakes should be removed if possible after the first, full growing season.

These young fruit trees need to be protected from our high intensity, desert sunlight for the first few years of growth. I would not recommend a protective wrapping around the trunk as this can actually create higher temperatures than just leaving it uncovered. You can use flat boards if you choose on the west or south sides of the trunk but it may be easier to paint the tree trunk and lower limbs with dilute, white latex paint.
Diluted White Latex Paint Applied to Peach Tree to Help Prevent Sunburn in Hot Desert Climates
Make sure the paint is latex and make sure it is diluted to at least a 50/50 mixture with water. You can use more water than this as long as painting the tree results in a much lighter surface that will reflect sunlight and help to keep the surface of the plant cooler than unprotected surfaces.

Paint all surfaces of the young tree which would be exposed to direct sunlight. Most importantly paint the south, west and northwest sides of the trunk as well as the upper surfaces of major limbs or scaffolds. Reducing the sunburning of juvenile woody plants will help to minimize attacks by boring insects.

Stop Cutting Asparagus Now

Asparagus Ferns - Asparagus Uncut
The asparagus harvest season is almost over and you should begin to not cut anymore spears and allow your spears of asparagus to grow and feather out as soon as it gets hot.  It is important to feed your asparagus as it ferns out to help it rebuild its crowns for next season’s crop.  You should add a high phosphorus fertilizer of your choice along with compost or light monthly applications of a high grade of fertilizer.

Control Peach Twig Borer Now

Peach twig borers are flying now and some are getting into early maturing peaches, nectarines and apricots. These small, brown flying months cause some slight damage to new growth in these trees and cause wormy fruit. 
Damage to New Growth of Peach Due to Peach Twig Borer
They usually enter the stem end of the fruit where you can see some frass or light brown grounds left behind by the larva or worm.
Peach Twig Borer Frass Near Stem End on Apricot
 These can be easily controlled with sprays of either spinosad or Bt, both of which are organic sprays. Follow label directions and apply regularly. Add a surfactant such as a spreader/sticker or small amount of unscented liquid detergent. Spray the entire tree, particularly the fruit. 
Peach Twig Borer Larva Causing Wormy Peaches

Spinosad by Ferti-Loam

Spinosad by Monterey

Windy Weather Means Irrigating a Bit Sooner

The past few days have been unusually windy.  In fact, this entire spring has been a windier year than normal.  The saving grace is that it is unusually cool for this time of year.  Normally I would be irrigating immediately following strong winds such as we had.  If the plants were on drip irrigation I might even be irrigating during the heavy winds.
There are four factors which are the primary driving forces behind the use of water by plants.  The two which are most responsible are wind and bright, continuous light or light intensity.  The other two, temperature and humidity, are also important and increasing temperature nearly always accompanies increasing light intensity.  Bright days nearly always indicate warmer days regardless of whether it is winter or summer.
Why is this important to know?  Daily changes in the weather are what I use to fine tune my irrigations from week to week.  For example if my normal days to irrigate in May are on Tuesdays and Saturdays and my plants just went through some horrendous winds on Saturday and Sunday I might irrigate the day after the heavy winds.  So instead of waiting until Tuesday I might elect to irrigate one day earlier (or even during windy weather if everything is being drip irrigated). 
Late next month in June is a time normally when temperatures start approaching or exceeding 110° F.  As we begin to break 110° F on a regular basis, I will consider adjusting our irrigations of deep rooted plants like trees and shrubs to three times a week instead of two. 
However, if weather stays relatively cool I might keep irrigations to twice a week unless there are strong winds which will substantially increase the use of water by plants.  High temperatures and gusty winds always drives water use up and should make you consider running an early irrigation cycle if you are permitted.

Sunday, May 29, 2011

Fruit Tree Recommendations for Southern Nevada Download

Fruit Tree Recommendations for Southern Nevada -