FAQs

Question:

We have just moved into a home that was not lived in for several months. There are several centipedes in the house. What can we do to get rid of them?

Answer

The giant desert centipede (Scolopendra heros) are native to our high deserts. They are multi-segmented, elongated arthropods that have a distinct head and one pair of legs per body segment. They are flattened, fast moving predators, and generally brownish-yellow in color. Centipedes are 2.5 to 25 centimeter or more in length, with 10 to over 100 legs depending on the species. The giant desert centipede has a pseudo head" for a tail which mimics the head in look and movement when preyed upon. This presumably will give the animal a fighting chance when attacked by birds, bats or other enemies. These critters hide in cool places- under rocks, boards, loose bark or in other dark moist places during the day. They actively seek prey at night, stunning or killing it with modified legs, called gnathopods, that are equipped with a poison gland. Their prey are insects and other arthropods, and in the case of the giant desert centipede small mammals or birds also. Their bite is not mortal to humans but is painful, similar to a wasp sting."

Control

If a centipede is found in the house capture it in a box, bag or sack using gloved hands, a stick or tongs for guidance. Release it outside where it can prey on other insects like cockroaches. Sealing up the house, particularly outside door thresholds or holes where pipes enter the house, should prevent this beneficial arthropod from entering your living space.

Source

Venomous Animals of Arizona. 1992. Robert L. Smith. The University of Arizona Cooperative Extension, Tucson, AZ. pp. 24-26.

Question:

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

Answer

These 'bugs' are really spider 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 red spider mite is a general feeder and usually does not cause excessive damage on plants. If they do, you can destroy them by stepping on them or spraying with insecticidal soap.

Question:

When should I dethatch my lawn?

Answer

It depends on the type of lawn you have. Dethatching is done with either a machine rented from a rental shop or with specialized rakes that give the user a very good workout! Dethatching is done to remove excessive build up of plant materials that lies just beneath or just on top of the soil. The former are rhizomes and the later stolons. Stolons are stems that creep" on top of the soil and rhizomes are underground stems. Both serve as sites from where new grass plants are formed. Dethatching is not for the removal of built-up grass leaf blades in the sod. These normally decompose naturally. Fescue type lawns do not have rhizomes or stolons and are never dethatched. Bluegrass has only rhizomes. These are cool-season plants and grow best with cool temperatures. Burmudagrass can spreads by means of seeds, rhizomes and stolons and is a warm-season grass, growing best in warm weather. Dethatching is a damaging procedure and should be done only when plants are vigorously growing and have plenty of time to recover from the damage caused by the machine or rake. Therefore, dethatch burmudagrass lawns about a month after it is growing well, normally the end of May or June. Bluegrass is rarely in need of dethatching but if need should be done in later September or October. Fescues never need to be dethatched because they do not produce stolons or rhizomes."

Question:

When is the proper time to plant a turf lawn?

Answer

Because of our climate in Cochise County we can grow two general classes of turf. They are warm season and cool season grasses. Warm season grasses are those that flourish during spring and summer and then go dormant (brown) in the fall and winter. Warm season grasses include bermuda, buffalo grass, grama grass, sideoats, St. Augustine and zoysiagrass. These grasses should be sown, plugged, stolonizing or sprigging, (planting shoots with leaves) or sodded in the spring when temperatures are warming up. Cool season grasses grow best during cool weather but are green during the heat of summer if they are watered. They will remain green if winters are mild. Cool season grassed include Kentucky bluegrass, the fescues and ryegrasses. Cool season grasses are best sown or sodded in the late summer (late August or September) or early fall. The second best time to plant or sod these grasses is in early spring.

Question:

When should I plant native warm season grasses and how should I prepare the soil?

Answer

Warm season native grasses include but are not limited to the bluestems, buffalos, gramas, Indian rices, lovegrasses, sideoats and wheatgrasses. Planting of most of these grasses should occur just before the monsoon rainy season begin in July. Seeding rates vary between different grass species. For example Buffalo grass is seeded at 3 to 4 pounds and blue grama grass is seed at 1 to 2 pounds per 1,000 square feet. In most situations it is advisable to mix 2 or more compatible species together and sow them so there is more diversity in the planting.

For best germination and stand till the soil 4 to 6 inches deep, (this is very necessary on new construction sites because of compacted soil), rake smooth, spread seed, and top dress with compost or composed manure. The dark compost will warm the soil and hold moisture which aids in germination.

Many of these warm season grasses make attractive landscape areas but are not suited to heavy traffic and play. However, breeding programs are currently developing turf type lawn grasses from native warm season grass species that will withstand traffic. Also, many of these grasses are more drought tolerant than the more traditional turf grass and require less water than bermuda grass.

Question:

Last year my bermuda grass lawn seemed yellow in the spring so nitrogen fertilizer was applied. The lawn looked better but later in the summer it looked yellow again. Nitrogen was applied but the lawn was still yellow. Why did the spring application of nitrogen work and the summer application did not?

Answer

Nitrogen is needed for fast spring growth. Iron becomes less available in alkaline soils as the season progresses. Nitrogen deficiency shows up in older leaves that are yellow. Plants can break down nitrogen containing compounds and move it where the greatest need is, normally growing points, leaving older tissues yellow. On the other hand iron is used by plants to produce several compounds including chlorophyll. Plants can not broken down iron and moved it to other parts of the of the plant. As the growing season progresses alkaline soils bind iron and it becomes less available. So new leaves become chlorotic. Iron chlorosis has visual symptoms of green veins on new leaves but the interveinal spaces are yellow. Excessive watering can also cause iron chlorosis because soil oxygen pore space is filled with water. No oxygen- no root growth and little if any iron uptake.

Control

To correct iron deficiency, apply either ferrous sulphate, ferrous ammonium sulphate, or a chelated iron source to the lawn following label directions when first symptoms appear. Chelates are more expensive but will last longer than the other products, which will need to be applied more often. Usually two to four ounces of product are applied per 1,000 square feet. Mix the product with enough water to apply one to three gallons of water per 1,000 square feet of lawn area. Spray the lawn in the morning letting the spray dry all day long. Water the lawn before mowing. Excess iron spray will be stored in the soil and/or taken up by the turfgrass. Be careful not to stain concrete areas with the iron spray. Within a few days the turf should start greening up.

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:

Should I fertilize and water my house plants during the winter?

Answer

Houseplants are generally tropical in origin and survive best in warm humid environments. Houseplants need to be watered because of the limited soil volume they are confined to. House temperatures are warm and allow plants to continue to grow. The best way to determine soil moisture is to stick a finger in the soil one to two inches. If the soil feels dry, water; if soil feels moist, don't water. Fertilizing houseplants during in the winter months is not encouraged because of reduced light from the sun. However, if you are spoon feeding" your plants, that is giving a little fertilizer at each watering, cut back on the fertilizer by giving 1/3 to 1/2 the normal amount. Many house plants need high humidity to be "happy", this is especially true with ferns. With forced air heating in many homes, house humidity can be lower during the winter than during the hot summer because of swamp cooler use. Humidity can be created by placing the potted plant on top of a pebble filled shallow dish. Fill the dish with water as needed, maintaining the water level near the top. The dish should have a diameter nearly as large as the plant diameter. The pebbles are import so that the potted plant is not sitting in water which will cause soil saturation, and thus root rot. As the water evaporates a humid environment is created in which a tropical plant will grow and thrive. This is much better than using a squirt bottle three times a day to try and humidify the plant!

Question:

I have elm trees that have beetles that become quite a pest. They eat the leaves. How can I get rid of them?

Answer

A sure way to get rid of elm leaf beetles is to cut down your tree(s) and those of your neighbor's! The larva of the beetles are eating the leaves so you must get rid of them. You can spray Bacillus thuringiensis or B.T., the San Diego strain. This product is sold under several trade names and is an organic insecticide that kills insect larva only and is not harmful to other insects or animals. B.T. is a natural occurring soil bacteria that must be sprayed on the leaves and the treated leaves eaten by the larva. B.T. is washed off by rain and must be reapplied. Another solution is to spray a 2 foot band of Sevin insecticide around the tree trunk 6 to 8 feet above the ground. The elm leaf beetle larva travel down the tree trunk to pupate on the lower trunk or near the soil line. Crossing the Sevin strip will kill the larva and over time reduce the insect population according to University of California entomologists. This treatment also will not destroy adults so if there are a lot of elm trees in you neighborhood other elm leaf beetles will fly to your trees and lay eggs. However, these treatments can significantly reduce larval populations and damage to tree leaves.

Question:

My ash, plum and pomegranate leaf margins are turning brown and drying up. The leaves are yellowish in color with some green remaining between the veins. I have been watering the trees using a well. They are planted in my lawn. I used "Weed and Feed" on the lawn this spring and again during the summer. The trees are just looking sick and I am feeling like the trees.

Answer

The trees are showing the signs of herbicide damage. "Weed and Feed" products contain fertilizer and 2,4-D herbicide. Inert particles like clay are coated with the herbicide which releases into the soil when watered. The herbicide 2,4-D will kill many broadleaf weeds in the lawn. However, the herbicide also can damage or kill other broadleaf plants. These trees are showing symptoms but did not receive a large enough dose to kill them. The herbicide reached the shallow rooted trees, was absorbed and you see the symptoms in the leaves.

Control

Do not apply 2,4-D type herbicides, (as a spray or in a "Weed and Feed" product), where desired broadleaf plants will absorb them through the roots or leaves. Many broadleaves like roses and grapes are very sensitive to 2,4-D type herbicides. The trees will most likely not show symptoms in the spring. For now the leaves will have to drop so that the trees will not look sick.

Just a note on the herbicide 2,4-Dichlorophenoxyacetic acid, (the chemical name), or 2,4-D for short and related compounds. This herbicide comes in several different formulations. If it is to be used around plants that are susceptible, i.e. broadleaf plants, use an amine formulation. It is less volatile than an ester formulation. You must read the label and find the chemical name. If amine or ester appears in the chemical name you will know the type of formulation.

Question:

I have a number of cottonwood trees, (Populus fremontii), that are growing around the edge of our pond. The younger trees that I planted over the past two years are doing fine. The trees that are older, with trunk diameters of 18 to 24 inches have been dying or dead limbs that appeared this summer. We saw some black beetles under the bark in channels carved out of the wood. What are these and what can we do to save these trees?

Answer

After seeing samples of the branches it was determined that damage was caused by a large larval stage of the carpenterworm moth, Prionoxystus robiniae (Peck). The black beetles you saw were secondary pests and not causing the damage. This insect attacks weak trees. Your trees were weakened by three spring frosts that defoliated the trees. This stress allowed the hatching insect larvae to enter the trees. This wood- boring insect takes one or two years to complete its life cycle in warm areas but in cooler areas as long as four years. The eggs are laid shortly after the moths emerge in the spring and continues for about a month. The female can lay 300 to 600 eggs in a sticky mass on host branches or trunk. The larvae hatch and bore into the sapwood where it remains most of the larval stage, going through eight to 31 instar stages. As they mature they extend their tunnels into the heartwood. As the larvae bore they produce large amounts of frass, (droppings), and sawdust. In fact the frass looks like excelsior from cooler pads. This clings in mass to the external bark. Tunnels maybe up to 18 mm, ( 3/4) in width. This boring can be disastrous to host trees by killing limbs which are subject to wind breakage, also ruining the wood for saw-log purposes. Host trees include elm, ash , birch, black locust, oak, cottonwood, maple, willow, apricot, pear and an occasional ornamental shrub. The carpenterworm is distributed all over the United States and all bordering Canadian Provinces."

Control

Remove all dead or dying limbs and burn them to kill the larvae. Make sure that the trees are receiving adequate water and nutrients, because the best defense is a healthy tree. Applying a small amount, (1/16 to 1/8 pound per inch of trunk diameter) of nitrogen fertilizer will help strengthen the tree this fall. Too much will invigorate the tree that is preparing for winter dormancy. This next spring apply four times the fall amount in two or three applications. Place fertilizer around the drip line and water in. Insecticides applied in the spring might help destroy other eggs that will be laid, but will do little to destroy the larvae that are feeding underneath the protective bark. Systemic insecticides are of little worth with such large trees.

Question:

An Arizona oak tree that is growing in the middle of my patio has dead branches under the living branches and its leaves that are falling. The tree is quite large with a trunk diameter of close to three feet. Natural rainfall is the only water it receives. The patio was build two years ago. Why is this happening? Don't oaks stay green year around?

Answer

The oak tree is a very large and old specimen. An oak that has a diameter of nearly three feet must be at least 100 to 150 years old. The dead branches are those that are under the living ones. When new growth occurs older branches can be shaded out and not produce leaves; they have served their function and die. Prune out the dead branches to make the tree more sightly. Leaves of evergreen do not live forever but their don't fall all at once. During certain times of the year it is natural for some evergreen leaves to fall. By placing a patio around the tree perhaps some of the roots do not have the access they once did to rainfall. However, it must be remembered that mature trees normally have actively feeding roots only 40 to 60% of the distance in from the drip line towards the trunk. Remember that trees do not live forever. Only some species will out live humans.

Question:

I have some Eldarica pines that have funny curling needles. They occur on last years needles but form nearly complete circles. What is happening to these needle and will it affect the future growth of the trees?

Answer

The damage to the needles is caused by eriophyid mites. There are probably more unknown and undescribed species of these mites than any other group of arthropods. They are very small and are measured in micrometers or microns. They are worm-like and slow moving. Injury in conifer species is expressed by chlorotic needles, and/or dwarf, distorted, or short needles. Also by rosette bud/needle clusters similar to a witches broom, by galls, and by partial defoliation of old as well as the current season's needles. Eriophyid mites are found in or on the buds and foliage of all North American conifer species. Many other plants are affected by these animals including deciduous trees and shrub.

Control

There are no control measures that are recommended for eriophyid mites on conifers. The effects of the damage will not cause the plants to die, however, they can cause unusual growth.

Source

Insects That Feed on Trees and Shrubs. Warren T. Johnson and Howard H. Lyon. 1991. Cornell University Press. page 122.

Question:

I have a pine tree that has masses of sap that look like large bubbles or balloons. These occur on small branches near the tips. Some of the needles are dead or dying. What is causing this and what can I do to prevent it?

Answer

The mass of sap you see is the result of an insect larvae that is living inside of the blister-like bubble. If you burst the bubble" you will find a pitch twig moth larvae. There are several species of pitch moths, however the one you have is most likely Petrova comstockiana (Fernald). Eggs are laid singly on the bark of limbs, the hatching larvae tunnel into the bark and cambium region and establish feeding sites. The pine tree exudes pitch and the larvae then uses the pitch to construct a "home" which includes frass or insect droppings. A mature larva is about 25 millimeters long and has a brownish head and light yellow body. Pupation takes place within the pitch mass and adults emerge during the summer months. In some species about half the population requires one year to complete a life cycle; the other half requires 2 years. In the case of this larvae it will feed on one site for one year then move to a new site, usually a branch crotch, and feeds for another year. Thus two years are required for full development from the feeding stage to a pupal stage. Adult moths emerge only in the summer."

Control

Normally there is no need to control these insects. Populations in our area rarely if ever reach economically damaging proportions. If they are really a problem then killing the larvae by pruning out and burning the bubbles"; or open the bubble and impale the larvae on a wire will decrease the population."

Source

Insects That Feed on Trees and Shrubs, 2nd Edition. Warren T. Johnson and Howard H. Lyon. 1991. Page 72.

Question:

What are these fussy brown spots about 1/8th to 1/4 inch in diameter on the underside of oak leaves? The affected oak trees were planted last spring.

Answer

At first it looked like an egg mass of a lepidoptera, that is the moth and butterfly family. After further examination of the sample leaf it was determined to be a gall of the woolly leaf gall caused by cynipid wasp. Other gall forming insect are other wasps, aphids, psyllids or other insect. Most galls are formed as a reaction of the plant to larval feeding or adult egg laying. Most of the time the gall is formed from the reaction of chemicals that the insect secretes which produces mutation of plant cells. This abnormal tissue many times provides cover over the newly laid or hatched eggs. Also many times the inside gall tissue is a food source for newly hatched insects.

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