We generally associate insects with crop loss or disease transmission, but only a small number of insect species (less than 3%) are considered to be pests of humans, animals, or crops. Most insects are either outwardly beneficial or harmless. A number of them are predators, like lady beetles that live by feeding on aphids and their young. Then there are parasitic wasps, which can make one pest insect a host for a parasite therefore killing it. And of course there are the honeybees that act as pollinators of crops and also provide us with honey. Many insects are responsible for the decomposition of plant and animal matter, or they can be food for other creatures such as fish, frogs, birds and bats. Our life would be much more difficult without insects.
Beneficial Insects
Question:
What can I do about cicadas? They are so loud some years?
Answer
Periodic cicadas are distributed widely throughout the United States. The annual cicadas are present in summer, but the periodic species have long life cycles. A mature annual species is over two inches long, with a brown-black body, ornamented with clear wings that have green veins. Eyes are red to brown and quite large. There are six species of periodic cicadas in the United States. Three with a 17-year life cycle and three with a 13-year life cycle. When all life cycle coincide the male mating sounds can be deafening. Damage is caused by egg laying or ovipostiting females in twigs and branches of trees and shrubs. Branches having a diameter slightly larger than a pencil are preferred. A series of wounds are made in which eggs are laid. Weakened branches can break off or become permanently scarred and abnormal. Over 500 eggs can be deposited by one female. Nymphal cicadas hatch and then drop to the ground, burrow in to the soil, and feed on root sap. Depending on the species they will remain in soil for 17 or 13 years. At the end of this time they emerge from the ground through soil tubes they construct that are nearly a half an inch wide and a quarter inch high above the ground. Great numbers emerge at the same time, starting at dusk. They crawl up tree trunks or other objects, expand their wings, and begin their short adult life. The familiar song or call is made only by the males and is produced by a pair of drum like organs on the basal segments of the abdomen. These love calls can become very loud. Mating occurs and then egg laying begins, completing the life cycle.
Winter pruning and destruction of damaged limbs or twigs that contain eggs may decrease the population. Where feasible, valuable plants may be protected by covering them with shade cloth, cheesecloth, or hardware cloth. Natural enemies include birds, fungal diseases, and the cicada killer wasp, which kills some adults. Other predatory insects and mites may attack the eggs.
Insect Pests of Farm, Garden and Orchard. 1987. Davidson and Lyons. John Wiley and Sons. New York. Pp. 373-376.
Question:
I have a lot of grasshoppers in my yard. They are eating everything! How can I control them?
Answer
In Cochise County we have several species of grasshoppers, some are very colorful and grow quite large. Grasshoppers emerge in the spring from eggs laid last year. Grasshoppers hatch as miniature adults and molt 5 or 6 times during a period of 40 to 60 days. The young feed in the immediate vicinity and then move on to greener pastures" as food sources become depleted. Adults begin laying eggs shortly after they mature. Eggs are laid in the ground in pods that contain 15 to 75 eggs. A female can lay a total of 200 to 400 eggs during several weeks. Hatching rate depends on soil temperature and moisture and may continue for 3 months. Some species have more than one generation per year. Grasshoppers feed on grasses and other plants. When populations increase they will feed on nearly any kind of vegetation including bark and leaves of deciduous trees. Adults continue to feed until cold weather kills them. Natural weather cycles cause fluctuations in populations. Mild winters and warm, dry springs increase hopper populations. Cold, wet weather cause slow development and favor grasshopper diseases. Cool summers and early falls delay maturity and decrease the egg laying period."
If desert surrounds your property it can become very difficult to control grasshoppers because of large populations that can become migratory. Disturbing egg pods in the soil by tilling or plowing will expose egg pods, decreasing their viability. Young small hoppers are easier to control than adults. Picking and squashing" is a time consuming but effective control measure. Several chemicals insecticides will control grasshoppers as well as the abrasive nature of diatomaceous earth. Nosema locustae is a naturally occurring disease organism of grasshoppers. Bran and sweeteners are added to Nosema to attract the hoppers. Grasshopper are cannibalistic and infection spreads as healthy hoppers eat sick ones. Also the females pass this disease on to future generations through laid eggs. Nosema will take longer to destroy grasshopper populations than conventional pesticides. This is a living organism and must be stored in the refrigerator and has a limited shelf life. Contact your local nursery or garden catalog for current recommendations. Always read the label of pesticides and use them accordingly."
Insect Pests of Farm, Garden, and Orchard. 1979. R.H. Davidson and W.F. Lyon. pp. 117-119.
Question:
I see some bees coming around my hummingbird feeder. Is it possible these are the 'killer' bees that have killed dogs and attacked people?
Answer
There is no way of knowing if the bees you see are the Africanized Honeybee (AHB). Visually EHB and AHB are identical to each other. Experts can not tell them apart with out laboratory analysis.
They are not killer bees, even though the media makes it sounds as if these insects require human flesh to complete their life cycle! Honeybees are not native to the Americas. There are six species of honeybees in the world and over 20,000 known species of bees. European Honeybees (EHB) were brought to America by immigrants and known by Native Americans as white man's lice. In the mid 1950s, bee researchers imported some AHB into Brazil to breed with EHB to hopefully increase the EHB's honey production in tropical environments. Some AHB escaped and began moving north. They arrived in south Texas 1992.
Honeybees defend there colonies or home vigorously because this is where their young are reared and food is stored. In nature, bears, skunks and other animals try to steal their stored food. Honeybees are aggravated by motions of larger dark objects, animal smells like leather and perfumes, shampoos and perspiration. Both bee species sting in the same way, going for the head and eyes, with a barbed stinger that remains in the victim. AHB venom is just as potent as EHB venom. Venom is pumped from a bulb on the top end of the stinger through it into flesh. Stingers should be scraped out with a knife, finger nail or credit card. Trying to pull out a stinger will squeeze more venom into the victim's flesh.
A lone foraging bee whether an EHB or AHB will not bother you if you do not bother it. Swarms of honeybees are seen during the spring and summer and with AHB swarm even in the fall and warm winters. About half of the old colonies bees accompany the queen. This is the way that honeybees divide and establish colony and form another. They are not defensive because they are looking for a home and have nothing to defend. Once a place is located by scout bees and the swarm then set up house keeping. When the new colony is established with young and food stores the bees will defend it.
AHB will defend their colony more vigorously than EHB. EHB have been selected and red for centuries to be docile and productive. AHB are just like EHB but just have a bad aggressive attitude. More people die in the United States from lighting than from bee stings. The numbers perhaps will increase with the AHB but will not likely surpass lightning deaths.
It is advised to close holes and cracks in homes, barns and out-buildings that are larger than a pencil eraser. Use caulk, boards or other suitable materials. Make weekly inspections of wood piles, abandoned cars, old tires and junk piles which could make suitable place for swarming bees to establish new colonies. If new colonies are found call certified bee removal personnel such as beekeeper, pest control operators or the Arizona Department of Agriculture so action can be initiated.
If you or someone else is stung run into a house or vehicle to get away from other bees. A sting pheromone alerts other bees to sting also. Do not swat at the bees with your hands and arms just run to safety. If you are out in the open you must run for a quarter or half mile to distance yourself from the bees. We will have to learn to live with AHB but there is little difference from EHB.
Question:
How can I rid my property of gophers? They are making mounds and destroying some trees and bulbs in my garden.
Answer
Pocket gophers are burrowing rodents. So named because they have fur-lined, outer pouches on each cheek, that can be turned inside out to carry food. Pocket gophers are strict herbivores and any animal material in their diets appears to be accidental. These rodents feed on roots, bulbs, corms or rhizomes they encounter when digging. They can pull vegetation into their tunnels from down below. They will also venture out of their runs a body length or so into the open to feed on above ground plant material. Pocket gophers burrows are a system of tunnels totaling up to 200 yards with densities of 6 to 8 rodents per acre a high population. The main burrow is generally 2 to 3 inches in diameter, depending on the size of the occupant and is 4 to 18 inches beneath the soil surface depending on the soil type. Lighter textured sandy soils will have deeper burrows than heavier clay soils. The soils ability to withstand cave-ins determines burrow depth, although some parts of the burrow maybe 5 to 6 feet deep. Deeper branches off of the main burrow are used for nests and food caches. Enlargements along the main burrow are usually feeding and resting stations. Nests chambers are lined with dry grass and other plant materials. A less apparent requirement of burrow depth is the need for fresh air and exhaled gases to pass through the soil to and from the gopher's tunnel. Therefore, heavy clay soils or those that are continuously wet, diffuse gases poorly and are not suitable for gophers. The fan shaped mound of soil seen on the surface is the excavated soil that is pushed out of the main burrow through a lateral branch. Pocket gophers are usually solitary except during the breeding season. Gophers have 1 or 2 litters per year and average 3 to 4 babies per litter, but 1 to 10 may be born. Birth is usually from March through June, after 18 or 19 days of gestation. Predators of pocket gophers that pursue them underground are weasels, perhaps spotted skunks and several snakes including bull and rattlesnakes. Dogs and cats may dig or capture them above ground along with other similar wildlife.
Exclusion cages may be made by using 1/4 to 1/2 inch mesh hardware cloth which are placed in the ground and planted into. Plastic netting placed under newly planted seed beds or bare root plants may slow gophers down. There are no registered chemical repellents other than moth balls which are ineffective. Also noise devices and plants reported to repel pocket gophers have proven to be ineffective. Gopher traps are effective if a gopher runs into one. They are placed in the burrow and should have a wire or twine tied to the trap and an above ground stake so it can be retrieved when a gopher is caught. Perhaps the best way to rid your garden is to use toxic baits. These are usually grains that have be coated with poison. Currently the anitcoagulant chlorophacinone formulated with a 0.005% active ingredient is available. This product is placed on grain and then formed in to small bars which are held together with a waxy material. Another poison is zinc phosphide, (2% active ingredient), is also available as a grain bait. The best way to find the burrow is with a pointed steel rod cane that is used by probing the area a foot or two away from a mound. Remember that the mound is a short lateral tunnel off of the main burrow where soil is removed from the burrow. When a burrow is found the rod will go easily through the soil. Dig down to the tunnel, locating the burrow hole on each sides of the hole you dug. Place some bait in each burrow hole and cover the baited burrow hole with a weed or grass so that backfill soil will not fall on top of the bait. Fill in the hole and then knock down any of the soil mounds within a 10 to 15 foot radius of where you dug a hole. Come back in a week and see if there are new mounds and bait those. Over time you will get the pocket gophers under control.
Controlling Pocket Gophers in New Mexico. New Mexico State University Extension Publication 400 L-2, pp. 5.
Question:
We are having problems with deer eating leaves and shoots on our fruit trees. We have a 4 foot high fence which obviously is not high enough to keep them out. I've been thinking of installing a one or two strand electric fence above the existing one so the fence is about 6 or 7 feet high. I have also heard about baiting the electric fence to train the deer to keep away. Do you have any advise on this subject?
Answer
Yes, a taller fence can keep out most deer. Deer will also crawl under fences if not close to the ground and secure. Deer have hollow hairs that do not conduct electricity and so they do not get shocked by electric fences. You can train them however. The most effective way that I know of is by making 2-3 inch wide strips of aluminum foil and maybe a foot long. Heavy duty foil is the most robust. Fold the foil over the wire and staple the strip ends together. Place some peanut butter on the foil. Place these training devices" every 20 feet or so a long the fence. Electrify the fence. Because of the dry conditions we are experiencing there is a lack of native vegetation. Hunger and thirsty wildlife will take chances they normal would not while looking for food and/or water. If you create a garden oasis in the desert you will have more wildlife pressure during drought conditions."
Question:
What is chewing out perfect circles on the leaves of my plants?
Answer
This is the work of the Leafcutter Bee (Megachile sidalceae). Leafcutter bees are solitary, small bees with black or gray bodies with white hair forming bands on the abdomen. Females cut out plant material from roses, ash, redbud, and other plants with smooth leaves. She uses the materials to construct cells and gathers pollen and nectar to make bee bread for the cell. She then lays eggs on the bee bread and closes the cell. Although unsightly, the damage leafcutter bees do to plants is cosmetic and will not kill the plant. No control is necessary. Bees are very important pollinators. Insects and animals pollinate over 70 percent of crops that we rely on for food, fibers, and medicines and 90 percent of landscape flowering plants, shrubs, and trees. Bees foraging for nectar and pollen in the garden are harmless and will not sting unless provoked to do so."
Question:
There are hundreds of thousands, perhaps even millions of insects that are long and black with grey spots that look like beetles have been swarming onto our property. They have been stripping our trees and vegetable garden with their voracious appetites. What are these insects? We have sprayed them and they die quite easily. What can we do about them?
Answer
What you have experienced are blister beetles. In particular the spotted blister beetle, Epicauta maculata, according to my reference books. There are other types of blister beetles that have stripes or are solid black in color and even a metallic Arizona blister beetle. Blister beetles are elongated beetles 3/8 to 1 1/8" long. Their broad head is usually wider than their prothorax and connected by a narrow neck. The wings and body are soft and frequently the tip of the abdomen is exposed. Eggs clusters of up to 100 are laid in holes in the soil and hatch in 10 to 21 days. Larvae burrow in search of grasshopper eggs, pupate in 2 weeks, and over winter in the soil. Larvae are beneficial. One larvae can destroy 30 or more grasshopper eggs, which is the total laid by a single grasshopper. The active parasitic larvae can gain access to bee nests by attaching themselves to foraging bees. Adults of the several species have similar habits. They appear in the late spring through summer. The entire population will emerge in a very short period and forage on many different host plants. They feed on foliage, usually in large numbers, and after defoliating a plant will migrate to others. Usually only one generation is produced each year. All species contain a blistering substance, cantharadin. This material is extracted from a species in southern Europe, the Spanishfly, and used as a drug. Some species will secrete blistering materials or oily substances as a defensive action. Sometimes alfalfa hay that is bailed will have large populations in it and when eaten by livestock can cause blisters in the mouth and on the tongue, causing sores that will cause animals to stop eating because of the pain.
How to Know the Insects. 1978. Roger G. Bland and H.E. Jaques. Page 223. Insect Pests of Farm, Garden, and Orchard, 7th Edition. 1979. Ralph H. Davidson and William F. Lyon. Pages 265-266.
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."
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.
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."
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.