Coarse mulch not suitable for vegetables

The transplant sale at the University of Nevada Cooperative Extension Master Gardener Orchard in North Las Vegas has been extended another week. Last Saturday was a horrible day for transplants due to winds and we had to close down early. We made a decision to extend the sale one more week. Available Saturday will be all the normal spring vegetable garden transplants and some very unique ones as well.

For more information on what will be available, times and location please call the master gardener help line at 257-5555.

Q: Is the mulch you give away free at the UNCE orchard suitable for veggie gardens?

A: The mulch we use at the orchard for our fruit trees and give away to the public is too coarse to use as vegetable garden mulch. The wood mulch we get is from First Choice Tree Service, is termed "green waste" and is from a variety of different trees that are removed from Las Vegas landscapes.

We do not accept green waste from mesquite due to the thorns or palms because it decomposes so slowly. If this mulch was screened to remove the large pieces, it might be all right.

Normally, green waste is sent to public landfills where it is buried. This waste has been diverted from our landfills and, instead, made available to the public. The benefits of using green waste in landscapes are numerous. I will be glad to send to you a publication on its benefits if you e-mail me.

In the garden I use compost as a surface mulch to cover seed for very small seedlings like lettuce and then straw as seedlings emerge. I also think shredded newspaper should work well. The ink now is soy based and not lead based. Contrary to some other sources of information, I have used grass clippings (untreated with pesticides) as a surface mulch for seedlings as well.

Q: I remember reading your explanation for the recent loss of agave in our area, but cannot remember your suggestion for treatment as I did not have a problem at the time. However, I have now lost several of them due to insects and would like to save the remaining ones.

A: The main problem is the agave weevil, a small dark beetle with a snout that lays its eggs in the crotches of the fleshy leaves. Feeding damage may be apparent as small holes near the base of the fleshy leaves. The eggs deposited in the leaf crotches hatch and small white larvae feed on the crown and root system of the agave.

We would normally see agave begin to dieback or die in June and July. Usually the older leaves start to brown or dry and die. This is usually a sign of agave weevil injury and death soon follows. This would mean that insecticide treatment should be done about two months prior to these dates with follow-up applications as the label recommends and varies with the pesticide.

Unfortunately, there is not a lot of information about this pest and its control. The problem is that some pesticides known to probably work (diazinon, Sevin, any grub control chemical) may no longer be available or may not have a label that permits its use on agave for that insect. So even if it works, I cannot recommend it because of its labeling.

But if you do decide on chemical treatment, look for chemicals for grub control and start applying in March, a month apart through July.

Bob Morris is an associate professor with the University of Nevada Cooperative Extension. Direct gardening questions to the master gardener hot line at 257-5555 or contact Morris by e-mail at morrisr@unce.unr.edu.