Mole Control: DIY Trap Construction

Mole control methods range the gamut from simple and non-toxic to chemical-based and complex. My simple mole trap was founded on the basis of field trials and personal convictions I hold regarding the environment and its inhabitants. Prior research had been done early on in the search for a humane and sustainable method for dealing with the mole problem here at Highland Hill Farm.

Highland Hill Farm is a 22-acre parcel located in the steep, rocky foothills of Mt. Sunapee. Agriculturally speaking, this area of New Hampshire is better suited for grazing pasture and forestry than for large-scale horticulture. A milestone in sustainability and independence here on the farm has been reached with the addition of a fully functioning, off-grid solar powered electrical system. Photovoltaic solar panels supply clean renewable power to maintain three farmstead dwellings as well as the two large chest freezers used to keep the summer produce fresh. This system was designed, constructed and fully funded by myself as a personal goal to act responsibly in support of the convictions I maintain toward environmental stewardship.

This article was written on a computer powered by the sun. I developed and experimented with various types of mole traps. The soil of my growing beds is rich and teeming with life, especially earthworms, the favorite food of the common northern mole (Talpa europaea ). Over the years I’ve been using a thick layer of mulch hay between the rows and around the spring plantings. This layer of hay provides cover for the moles, and as it decomposes it provides food for the earthworms. Plenty of worms create an environment conducive to plenty of moles. It’s not uncommon for me to step on a mole tunnel every third or fourth step, even around the grassy area near the trout pond. The infestation had gotten to the point where action had to be taken.

Moles undermine the root systems of plants, damaging the plants and making irrigation and nutrient up-take much more difficult. I believe the live trapping methods I’ve been developing have merit in helping farmers eradicate moles in an environmentally sound way, without toxic poisons or mechanical traps. I will continue to develop inexpensive, effective live mole traps through field trials at various farm locations throughout the area. The opportunity to develop new methods and designs may have crossover potential for other rodent pests.

mole trap
This trap is made from a common five-gallon bucket with about 70 quarter-inch holes drilled through the bottom.

Poisonous Bait

The main thrust of the commercial market relating to rodent eradication is focused on poisonous bait. Motomco Mole Killer claims, “one worm contains a lethal dose.” Unfortunately, the poisoned mole may become the prey of another unintended victim of the poisoned bait. This product is “not to be sold in AK, HI, NC and NY.” Another poison-based product, Moletox claims, “This exclusive formula pelleted bait has a unique cracked corn base, making it more palatable.” The problem here is that moles are exclusively carnivores/insectivores and would have no interest in cracked corn. This product is “not to be sold in CA, IN, NC, NH and Washington D.C.”

Clearly poisons should be an absolute last resort rather than a first choice.

Mechanical Traps

Mechanical traps offer a considerable advantage over poisons as far as environmental impacts are concerned. Most mechanical mole traps are designed to either impale or squeeze a mole, one at a time rendering the trap ineffective until it gets reset.

These traps are spring-loaded and come with their own warnings. The “innovative new scissor trap” is not to be sold in Alaska, Hawaii or North Carolina. These traps must be set over an active mole tunnel (of which there are many to choose from) and require a lot of vigilance on the part of the trapper. Here the trapper is going to spend a considerable amount of time chasing the moles, hit or miss, around the field in order to eradicate but a few.

Mole Control: Organic Mole Eradication

I had been on the search for a natural or organic method of mole eradication and have viewed many websites in a quest for a somewhat humane mole trap. The “sticky” trap seemed the best, consisting of a wide tape-like sheet that the moles were supposed to get stuck to. I made one but caught none. I’ve discovered moles are quite clever — they will test something and if they don’t like it after trying it once, they’ll stay away from it. Besides, there was no incentive for the moles to cut across the sticky sheet, no food, no reward, just a shortcut.

The mulch hay I lay over the bare soil each spring protects the microbial life-forms on the soil surface from solar UV rays that would otherwise sterilize the soil surface, killing that rich, vibrant biomass. Nature does her best to cover over bare soil with biomass in order to protect soil life-forms to keep them alive, protected from UV and erosion-proof.

I like using the mulch hay method because it is constantly building soil. The hay method also prevents compaction because the weight of man or equipment is distributed over the wider surface area of a thick hay mat. The mulch also holds in a lot of otherwise evaporated water and prevents erosion during a downpour.

During midday if I pull back some of the hay, earthworms will be on the surface of the soil. Earthworm castings and the soil-enriching properties of their activity are beneficial to soil conditions and therefore beneficial to the crops that the soil supports.

Star-nosed and common Eastern moles.

If a farmer has a lot of earthworms and some loose hay on the ground chances are that he/she will also have a host of moles tunneling about. The benefits of using mulch hay far outweigh discontinuing the practice due to the mole problem, but they are a problem nonetheless. I was transplanting small lettuce plants from an outside raised bed into the winter greenhouse. The raised bed lettuce was riddled with sub-surface tunnels to the extent that I was able to remove large swaths of young plants simply by running my hands through the soil 2 to 3 inches under the surface, nearly unobstructed, plowing from one tunnel into the next.

This was an advantage in transplanting, but in my other greenhouse where spinach was planted in raised beds the plants were stunted and sparse because of mole activity. Mole activity necessitates more frequent watering due to the fact that sub-surface tunneling dries the soil much faster. Safely trapping and removing the moles from the greenhouses and growing beds will increase production of both crop plants and earthworm populations.

The trapping methods I’ve employed so far have consisted of several trap designs and various baits. One design in particular has shown promise over previous ideas. The primarily successful live trap now in place on my farm has trapped as many as four moles in the same trap over a three-day cycle, indicating that this method could potentially serve to trap many more live moles over a longer period, therefore alleviating the tedious chore of checking multiple mechanical traps every day or even every three or four days.

Moles consume nearly their own weight in food each day. Moles are from a group of mammals called insectivores. This live-capture study may also prove useful in that moles could possibly be used in areas of insect infestation to remove problem insects, then recaptured live and relocated for use at other sites.

Moles have several other distinct features that may prove useful in further studies. Moles produce a toxin in their saliva that incapacitates earthworms, and moles have a high blood oxygen content. I believe these two features of the anatomy of moles are worthy of a great deal of study. Live capture could possibly be a very positive offshoot of this live trapping method in order to supply research labs.

At this time live moles are released into the wild a fair distance from the trap locations. The experience of dealing with an infestation of destructive mole activity on my farm led to the search for a nonpoisonous, non-violent, inexpensive and effective method of eradicating moles.

Through my own experimentation and expressions of ideas I’ve come up with a mole trap that works reasonably well, has no environmentally harmful side effects and is economically viable for just about anyone, anywhere. The trapping method described has been put to use here over the last few months of this past growing season and I have documented its simplicity and effectiveness.

Mole Control: Preparing the Trap

This study was a comparison between the various trap designs that resulted from my experiment and used in combinations of live baits. No commercial traps or poisons were used. The best bait was local — earthworms on the farm were dug up and refrigerated for future use. The traps are simple to construct using a common 5-gallon pail that is clean and odor-free. A pail that has been open and set outside for a while or one used for garden water and soil will work well. Drill about 70 quarter-inch holes through the bottom to allow water to move through and to give the mole a sense of openness below.

Locate the area most heavily infested for installation. Dig a hole that will loosely accommodate the bucket with plenty of room around the sides to be backfilled with loose soil. Set the bucket in about 3 inches deeper than the bucket open top so that the fill soil slopes downward around the open rim. Now fill about 25 to 30 percent of the bucket with rich, loose soil. Get a separate container for your live worms and place just enough soil in to keep the worms alive but not allow escape. Six to eight worms are plenty and should last three to four days. Depress the worm container into the rich bucket soil to keep it at ground temperature and the worms alive. While installing your trap it is helpful to stand on top of boards in order to prevent compaction. Moles commonly reuse the same tunnels so try to leave them undisturbed. Place a generous layer of mulch hay around your trap and cover with a piece of board that has been outside for a while. Your trap is set.

If you leave the trap unchecked for three days you may have a better success rate than if you check more often. There will be less human presence sensed by the moles, and if there are some moles already in the trap, more are likely to join the festive party. Always wear gloves to prevent human odors around the trap and to protect your skin from wily moles.

The design intent for these trapping materials and methods involves materials that are available and common to most every area of the world. The design is simple to build and install at a very low cost to the farmer, involving no special tooling or hard-to-find materials. The design does not require the purchase of mechanical devices or commercial poisons.

The intent is to produce a replicable trap for mole control that can be constructed and installed by the average farmer using materials commonly found on any farm. Aspects of agricultural sustainability are addressed by the ability of the farmer to be able to build his own traps from simple materials and bait them with worms or insects that are found on the farm.

This study focused primarily on star-nosed moles and the European mole, also known as the common mole or northern mole, common to this Northeast region. Northeastern farmers who have mole infestation problems will most likely be dealing with these species, and the trapping methods should work equally well throughout the region and beyond. The simple trap designed and used here has proven to be successful in trapping moles. This method is easily transferable — the most successful design/bait combination is available to farmers everywhere. It seems likely this simple trap could work successfully for mole control most anywhere in the world.

By David Brown. This article was originally published in the September 2013 issue of Acres U.S.A. magazine.

Aphid Control: Lady Beetle as Beneficial Insect

By Dr. Ayanava Majumdar

When searching for aphid control measures, turn to nature first. Numerous vendors sell beneficial insects via their websites along with offering plenty of useful information. For example, ARBICO Organics (Arizona), Orcon (California), Gardens Alive (Indiana), and Nature’s Control (Oregon) sell insect predators in large numbers and at least one vendor sells it as a “beneficial insect program” with weekly shipments adjusted to your pest control needs. Note that beneficial insects are slow acting in pest outbreak situations, so use beneficial insects preventively when pests are in low populations and have not overwhelmed the crops you are trying to protect. Follow the release instructions that come with the products, and modify your spray schedule to adjust for the presence of beneficial insects.

Aphid Control: Convergent Lady Beetle

The convergent lady beetle is a very common species of lady beetle among the numerous others present in any crop field. The convergent beetle is common in Alabama and also a very popular beneficial insect sold by companies. The insect name comes from the two white lines seen on the thorax of adult beetles that seem to merge together on the top.

The convergent lady beetle is a common species of lady beetle.

The number of dots can vary from none up to 13, so counting the dots alone is not a good identifier for this beetle. Larvae are black with rows of orange spots. Note that the lady beetle larva have chewing mouthparts and do not have the sickle shaped mandibles of the green lacewing larva. Eggs are elliptical and bright yellow in color; eggs are laid in clusters on plants with over 10 eggs per cluster. Eggs can also be laid in soil or plant debris. Pupae are immobile (non-feeding stage) and may be seen stuck to plant parts.

Adults and larvae feed on aphids. Adult beetles also feed on nectar and pollen. According to industry sources, each adult lady beetle can destroy about 5,000 aphids while the larvae can consume nearly 400 aphids in a week. In the absence of aphids, convergent beetles can also feed on moth eggs and small caterpillars. Female convergent beetles lay up to 1,000 eggs in ideal conditions and have a lifespan of one to three months. Larvae feed for three weeks and adults emerge two to five days after pupation.

Adults do not fly if air temperatures are below 55°F. There can be many generations of this insect every year.

lady bugs beneficial insects

The presence of a large number of lady beetles can indicate the presence of aphids. This insect can be the most abundant predator in cotton fields.

Many suppliers sell lady beetles in the adult stage when they are ready for field release (as shown in photo). The adult beetles can also be stored in their original package for some duration; provide some moisture to the lady beetles by sprinkling water on the packaging before release. Release lady beetles preferably during a cool evening. Lady beetles should be released when pest pressures are low and the beetles have something to feed on. Several weekly releases may be necessary to sustain a high predator pressure in an area. Industry sources recommend the release rate of 4,500 beetles for 2,500 square feet and much larger numbers for large areas. Out migration of adults once prey numbers dwindle is a major cause of loss of these powerful natural control agents.

Routine inundative release of beetles in large numbers can be effective in enclosed structures for aphid control. Remember that parasitoids and pathogens also act in conjunction with predators to provide natural control of pests. Do your own research before purchasing large batches of predators and carefully plan the release for the best effect. Follow the instructions that come with your purchase of beneficial insects.

Providing cover crops or shelter plants during the fall season is a good way to facilitate continuity of predators in an area.

Editor’s Note: This article appeared in the November 2012 issue of Acres U.S.A.

Dr. Ayanava Majumdar (Dr. A) is extension entomologist and state sustainable agricultural research coordinator at Auburn University, Alabama. Join him on the Alabama Vegetable IPM Facebook page for more information on sustainable crop production systems. 

Weed Management Techniques

By Dr. Harold Willis

Weeds are generally the first battle of the growing season. They seem to be especially bad in row crops such as corn. There are more kinds of noxious weeds today than there were 50 years ago, and thanks to herbicides, we now have many weed varieties resistant to the most powerful poisons we can throw at them, and even populations of soil bacteria in some areas of the corn belt that gobble up certain herbicides before they can kill the weeds!

The simple truth is that nearly all weeds grow best in poor soil—unbalanced, tight, depleted, “dead” soil. And that is just what our modern agricultural methods have created over the last few decades. In loose, fertile soil with the right balance of nutrients and beneficial organisms, weeds just don’t grow well, believe it or not. And crops do grow well, and can out-compete the weeds.

So how can you keep weeds under control? There are several ways. First of all, tillage methods that prepare a good seedbed in the row but leave a rough, poor seedbed between the rows (plus the use of a starter fertilizer) will allow the corn to sprout first and get ahead of the weeds. If weeds get a head start, many species release chemical secretions (phytotoxins) that inhibit crop growth, cutting yields (the process of one plant inhibiting another is called allelopathy). Many crops can do the same to weeds if they sprout first. Some weeds also reduce yield by competing for light, soil mois­ture, and nutrients. In Minnesota, grain yields have been reduced from 16 to 93% (51% average) by weeds, according to studies by Iowa State University. Weeds grow faster than corn in cool weather, so early-planted corn is at a disadvantage.

A second weapon in the fight against weeds is timely culti­vation, with shovel, rotary, or disk cultivators, rotary hoes, spike tooth and spring tooth harrows, etc. Some weeds are easiest to control when small, when their roots are shallow and the corn roots are already deep. Rotary hoes and rotary cultivators are most effective when the corn is small, but after it is over six inches tall, shovel cultivators are most effective. Be sure to only cultivate deep enough to kill weeds and not to prune the corn roots. As the season progresses, stay toward the middle of the row. Cultivation also has the benefit of breaking a crust and aerating the soil—which can greatly stimulate crop growth and health. If your soil has a crust, it is wise to cultivate even if there are few weeds to kill. A “dust mulch” formed by breaking a crust is also a good weed inhibitor. Another excellent tool to use is a disk hiller (pairs of disks, one on each side of the row with cultivator sweeps between rows), which will throw soil into a ridge against the stalks of older corn plants. This process will help control weeds, stimulate corn prop root growth, and form a furrow between the rows that will trap rainfall (hilling and row direction are therefore best at right angles to the slope of a hill). Other unusual weed cultivation methods are burning them to death with propane-fueled flame cultivators (good for small in-the-row weeds) and electrocuting them with a 15,000–20,000 volt electrostatic rig (which works on weeds taller than the crop, but the equipment is expensive).

A cornfield aerial view with weeds
A cornfield aerial view with weeds. Knowing what weeds are growing in your fields, and why, will help you manage your soil health.

One seldom-used method of cropping corn can reduce weeds; that is, intercropping, planting a different crop between the corn rows, such as soybeans or other legumes, forages, or sod. Gener­ally, corn yields are not reduced (although wider rows must be used), but the other crop will suffer from shading (but if a forage or grass will be in rotation the next year, then it will already be established). Experiments with planting alternating narrow strips (6 or 12 rows) of corn and soybeans have shown that corn yields can be increased 15 to 50 bushels per acre because of increased sunlight available to the outside rows of corn. The soybean yield is reduced 10 to 20%, however.

The use of herbicides to control weeds is at best a crutch, which only creates more problems than it solves. Besides killing plants, herbicides kill or at least upset beneficial soil organisms, leading to reduced humus production and tight, anaerobic, toxic soil—an ideal soil for weeds. Some herbicides actually stimulate germination of weeds other than the ones they kill. Also, herbicides or their break­ down products can pollute ground water and get into crops—the food we and our animals eat—with often-unknown consequences. If they absolutely have to be used to save a crop, herbicides can sometimes be reduced in dosage, especially if used with a surfactant (wetting agent). But with good soil, they may not be needed at all.

So that brings us to our last method of combating weeds and the ultimate solution in the long run—healthy soil. By having a loose, well-aerated soil (plenty of humus is the most effective way), and the right balance of nutrients (high calcium; more avail­able phosphorus than potassium), most weeds just won’t want to grow. They can actually become sick and die! I have seen it hap­pen, in less than one year of soil improvement.

Source: How to Grow Top Quality Corn

Non-Toxic Control of Common Insects

By Dr. Harold Willis
From How to Grow Top Quality Corn

There are dozens of kinds of insects that attack all parts of the corn plant—roots, stalk, leaves, and cob. As we have said, they are just part of nature’s clean-up crew, eating the sick plants. Healthy plants will have little or no damage and even pro­duce special chemicals that repel at least some pests. One such natural repellant is called DIMBOA, which is formed when corn tissue is injured and which repels young European corn borers, as well as the fungi that cause northern corn leaf blight infection and gibberella stalk and ear rots.

Insect pests also have their own natural enemies: other insects, parasites, and birds that keep them under control—if they aren’t poisoned themselves by over-use of insecticides. If insecticides have to be used to save a crop, effective kill can often still be ob­tained by reducing the dosage. But many pests can be adequately controlled by non-toxic methods, many of which were used dec­ades ago (see box on next page).

But the same as for weeds, the best long-range pest control is to have good soil which produces healthy, naturally resistant plants. Also, some hybrid varieties are more resistant to certain pests than others, and of course, some genetically engineered vari­eties contain the Bt gene and are resistant to corn borers.

diseased corn
Examples of bad stalks affected by insects and disease.
  1. Control of insects attacking seeds (seed corn maggot, wire­worms, and seed corn beetles): delay planting until conditions are good for rapid germination (wheel-track plant in dry years); replant between old rows if great damage (then cultivate out the worst stand); fall plowing; drain low spots.
  2. Control of root-eating insects (corn rootworm larvae, corn root aphids, white grubs, and grape colaspis larva): rotate or plant between old rows to escape large rootworm population; early plowing, disking, delayed planting, and extra phosphorus ferti­lizer for grape colaspis; disking to kill weeds and ant colonies for aphids; fall plowing and milky spore disease inoculant for white grubs.
  3. Control of insects feeding on underground part of stalk (wireworms, billbugs, sod webworms, and cutworms): plant other crop than corn if breaking sod; early fall plowing; reseed if neces­sary, then cultivate out worst stand; drain wet areas; early spring plowing and planting for cutworms.
  4. Control of insects feeding on corn leaves (armyworms, wooly bears, corn leaf aphid, corn flea beetle, grasshoppers, corn blotch leaf miner, chinch bug, cereal leaf beetle, 2-spotted mite, and thrips): early planting and resistant varieties for flea beetle; fall plowing and natural enemies for grasshoppers; don’t plant beside small grains for cereal leaf beetle; natural parasites and fungus disease for aphids; control of thrips, mites, wooly bears, and corn blotch leaf miner seldom necessary; no good control for armyworms (but they will avoid a healthy crop).
  5. Control of insects feeding in whorl, stalk, and ear (Europe­an corn borer, corn earworm, corn rootworm adults, stalk borers, fall armyworm, corn sap beetle, and picnic beetle): plant resist­ant varieties, midseason planting (not early or late), fall plowing, plow under or pulverize dead stalks, and bacterial disease inoculant (Bt) for European corn borer and stalk borers; plant resist­ant varieties for corn earworm; control other insects and diseases for sap and picnic beetles (they only feed on injured, unhealthy plants); no good control for fall armyworm (but they will avoid a healthy crop).

Source: How to Grow Top Quality Corn/(Advances in Corn Production, 1966; and Modern Corn Production, 2nd ed., 1975)