The Agent's Observations Aug 1995

QUESTION: What are the red fuzzy bugs that are climbing on my lawn? They have white markings on their backs and eight legs from 1/8th to nearly a 1/2 inch long. Do they harm my ornamental plants?

ANSWER: These "bugs" are really giant red velvet mites. They are not bugs but rather arachnids or members of the spider family which have four pairs of legs, two body parts, no antenna, and piercing, sucking mouth parts. These are the largest spider mites in our area. Most spider mites are quite small and a hand lens is needed to even see and identify them.

Control: The giant red velvet mite is a predator and feeds on other arthropods. Adults and nymphs also prey on termites. You can destroy them by stepping on them or spraying with insecticidal soap.

QUESTION: I have two things growing on my lawn. One is a black material that feels greasy when I touch it. It is on the ground and also on the blades of grass. The other material is orange-white in color and is moist to the touch but dries out and is chalky the next day. Any ideas of what these things are?

ANSWER: Did you change your oil over your lawn? If not then the black substance is a slime mold that is dormant in the soil until large amounts of moisture fall on the ground. The environmental conditions are then right for this organism to reproduce and migrate. The other material is a spore mat of a fungus that is in the soil. Again when environmental conditions are right the fungal organism, which lives in the soil, will send up a reproductive structure to spread spores there by reproducing.

Control: There is nothing that needs to be done to control these organisms. They were in the soil all along and have just put up reproductive structures. As the ground and air dry out they will disappear only to reappear when the environmental conditions are right.

QUESTION: My compost pile was doing very well, but after the recent rains we have had it really smells bad. What happened and what can I do about it?

ANSWER: Your compost pile is too wet and therefore has very little if any air available to the organisms that break down organic matter in it. Anaerobic respiration or fermentation has taken over and is causing the bad smells.

Control: Turn over the com post pile to get more air introduced into it. This will allow normal decomposition of the organic matter. Try and keep the compost pile as moist as a well rung-out sponge throughout the pile. In the desert the outside of the pile dries out quickly. Rewet the surface every couple of days as needed.

QUESTION: My tomatoes have cracks around the stem end and black sunken tissue on the blossom end. What is wrong?

ANSWER: Cracking around the stem is caused by high temperatures and watering practices. However, the cracking is genetic. There are varieties that do not crack. The "Mountain" series, including "Mountain Pride" and "Mountain Delight" from North Carolina do not crack. The other problem is called blossom end rot. It is a physiological condition that arises because of varying moisture in the soil. The plant cannot transport enough calcium to meet the demand in forming cell walls even though there is plenty in the soil. Most nutrients are carried in water to uptake sites on the root hairs. Sometimes a secondary fungus like sooty mold will colonize the tissue causing a black fungal growth. Other plants like squash, pepper, chili, and melons can have blossom end rot also.

Control: Water consistently and deeply and apply mulch to keep soil moisture consistent. Early fruit have more blossom end rot problems than fruit produced later, so be patient. The fruit is still edible just cut out the bad parts.

Rob Call
August, 1995