Long grass can protect fruit trees

I have about 20 fruit trees of various ages with a weedy grass cover that usually gets mowed about three times in the summer.

During this drought I am wondering what would be best for the trees: Let the grass grow long to cover the earth and roots, or mow it so that it does not draw so much water from the ground through transpiration?

— Paul

I think you are better off leaving the grass long. It acts as a mulch, cooling the soil and cutting down on evaporative loss of water from the soil.

However, be willing to let the grass go a bit dryer than you might otherwise, even to the point of it browning out. You’ll have to be careful not to hurt your fruit trees; but because they usually have deeper roots than the grass, you could probably get by watering deeply and more infrequently than you may have been.

I don’t know what kinds of grasses you have, but most of them are surprisingly resilient after drought, browning out when things are dry but greening back up once the water is regularly available again.

Our home and surrounding area were invaded by spider mites this past spring. I tried every chemically recommended product on the market. I finally resorted to the liquid dish soap, vegetable oil and water mixture and it seemed to “knock them down” some.

I am not sure that it was effective or just that we were at the end of the spider mite reproduction cycle or the end of the season. Could you give me any suggestions that may be useful for the next spider mite season?

­— Pat

Controlling spider mites can be a bit of a trick. Part of the problem we’ve had is that a lot of the “old line” miticides were phased out and we didn’t have a lot come out in the homeowner market to replace them until recently.

The good news is that there are some newer products that have come out in the past year or two that work pretty well.

Probably my first choice for chemical control is a material called Fluvalinate. This insecticide and miticide has been a staple in the commercial and greenhouse markets for years.

Another relative newcomer is an insecticide called Bifenthrin, another staple in the commercial market which controls a very wide range of insect and mite pests.

The last chemical insecticide is probably the oldest chemical pesticide out there: Malathion.

If you want to use an “organic” product, my two recommendations would be either insecticidal soap or a season- long spray oil. These products do a good job on spider mites, but they need to contact the insect to kill it, so you must to do an extra good job of covering the plant well when you do spray, and you should plan on having to spray a couple of times more than if you were using a chemical spray.

Bifenthrin and Malathion are both labeled for use on edible plants, while Fluvalinate is only labeled for ornamentals. The “organic” products are fine on fruits and vegetables.

No matter how you choose to go after them, it’s important to realize that you will need to be a bit consistent and persistent in controlling them. You’ll need to spray three times at seven- to 10-day intervals, making sure that you cover the underside of the leaves.

It’s important that you keep up with this schedule and not allow the mites to recover. If you do, you’ll have to start over.

You can also get surprisingly good control by spraying your plants every couple of days with a hard jet of cold water. Do this for a couple of weeks and be sure to spray the underside of the leaves. It’s an old-fashioned way to do it, but it works amazingly well.

Dennis Hill is the nursery manager at Bookcliff Gardens, http://www.bookcliffgardens.com. Send questions to Bookcliff Gardens, 755 26 Road, Grand Junction 81506; or email .(JavaScript must be enabled to view this email address).


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