Ask the Garden Sage: Health is best defense against insects

2014-07-27T10:00:00Z 2014-08-08T11:56:28Z Ask the Garden Sage: Health is best defense against insectsBy Peter Warren Special to the Arizona Daily Star Arizona Daily Star

I was told I have flat-headed borers in my apple tree. What can be done about these pests?

The flat-headed apple tree borer is a common species and although it is found mostly in the eastern and central U.S., it can be found throughout the country. There is a western species called the Pacific flathead borer that is more often seen west of the Rockies and these two species have similar biologies. They feed on a variety of trees and shrubs, including apple, maple, oak, sycamore, and rose.

The best defense against these insects is maintaining healthy trees and shrubs. Attacks from the borers are mostly found where there are cracks in the bark, cankers, pruning wounds, and suffering from other problems. Once they are in the trunk digging them out is the only solution and that may cause more problems for the tree. If they are known to be a problem in a certain area, preventive use of insecticides on the bark can limit new attacks if they coincide with egg laying and egg hatch one to two weeks later. Adults begin to emerge in early spring and after mating the females seek places to lay their eggs. The beetles are brownish gray, about 12 millimeters long, and can be seen on tree trunks during the spring scouting for egg laying sites.

I planted two Moringa trees in containers and I would like to plant more in the ground. Are there any problems with growing these in Arizona?

Moringa trees (Moringa oleifera) are native to India and belong to a family of trees with tropical and subtropical origin. They are grown for their nutritional content and much of the plant is edible. The main problem for Moringa trees in Arizona is cold temperatures. They typically freeze back to the ground below 32 degrees F and although they may grow back from the roots, they do not do well over the long term if not well protected from cold.

I rescued a tarantula being dragged away by a tarantula hawk. It’s been just over a month and I’ve been giving a drop of water every one or two days for maybe 2½ to 3 weeks. She’s regaining movement in her legs but no actual mobility.

I made the assumption from reading different info that the eggs weren’t laid on the tarantula until the wasp got it to the burrow. However, yesterday, when I opened the box to give water, I saw that a fair amount of clear liquid mixed with what looks like tiny bits of dark debris were dried on the paper towel. I cleaned her belly off which had a white powdery layer more to the left side, and it appears that there is a hole and maybe another just symmetrically across the abdomen, but only one had secreted. ... I’m afraid it could be the egg was already laid and has now implanted itself inside. The holes are about  one quarter to a third of the way up from spinneret end to her middle. Do you have any insight into this? I really want to do something to put her out of the misery if it’s eggs, but I’d like to be sure.

The tarantula hawk (Pepsis chrysothemis) stings the tarantula to paralyze it before dragging it to the burrow where she lays an egg and then closes the nest. It is likely the tarantula you rescued does not have an egg in it. The bad news is it may take months for the tarantula to recover from the sting and that is not even guaranteed. It is probably best not to interrupt the process next time and let nature take its course. There are plenty of tarantulas out there and not all will succumb to these wasps.

Peter Warren is the urban horticulture agent for the Pima County Cooperative Extension at the University of Arizona. He works with landscape professionals, urban farmers and homeowners to promote integrated pest management and best management practices for desert horticulture in Southern Arizona. Send questions to plwarren@cals.arizona.edu

Copyright 2014 Arizona Daily Star. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

Home improvement video

Featured businesses

View more...