Part of the Gryllotalpidae family, mole crickets are insects quite large in size, reaching up to 5 cm in length. They are related to crickets, grasshoppers, and locusts as well, but unlike their relatives, they are unable to jump, and travel by running quickly or flying. They are characterised by their shovel-like forelimbs, which are highly developed for burrowing. Due to them, they can be considered pests in most parts of the world, as they disturb the plants and their roots by digging for food and tunnelling through them. They live almost entirely below ground, digging tunnels of different kinds, which they utilize for different reasons, including feeding, escaping from predators, mating and raising their younglings.
Signs of infestation
As mole crickets love to burrow for any reason, their damage can be recognized by irregularly raised burrows and dying grass. They can dig themselves underground very rapidly, and can move along existing tunnels at high speed, both forwards and backwards. Establishing if an infestation is serous can be done by observing the damaged caused to the plants in the garden and the grass on your lawn. You can determine the size of the problem by creating a situation where the mole crickets are forced out of their burrows. You can make a mixture of water and dish soap and apply it on the ground, where you believe the infestation is occurring. A bucket of such concentrated mixture should do the trick, and in just a few minutes, you should be able to see the pests emerging from the ground. As they make their way to the surface, this is the best time when you can also apply an insecticide.
Mole crickets normally like lawns abundant in thatch and water. Improper mowing and excessive watering can lead to perfect conditions for the appearance and development of a mole cricket infestation. Their borrowings destroy the roots of plants and create areas of dead lawn that feels spongy when you walk on it. If you also see small piles of soil scattered on grass, it might also be a sign of infestation.
Unfortunately, the existing tunnels are not easily visible at the start of an infestation, but they do become more exposed, once the affected grass and plants dry up and die.
Most common problem areas are:
- under and around trees;
- under and around bushes;
- around decks and patios;
- any areas where leaf debris has collected.
Organic control methods
Depending on the life stage of the pest, different control methods can be applied. As moles overwinter in their burrows, they become active in the spring, when they start mating. Once the eggs hatch, they grow and eat during the summer, when most of the damage can be seen.
Applying a treatment in the winter, while they are hidden in the soil might stop them from further tunnelling, however the most effective treatment is the one applied in summer, which affects the nymphs, when they are vulnerable. Treatments against mole crickets should be done in time, as stopping the infestation once the damage is done, can prove to be more difficult. The easiest action taken against them is preventing their mating and increase in numbers.
Applying parasitic nematodes in spring can help, as they will spread through the soil, and once the females lay their eggs, the nematodes will stop their development. They also affect adults, and once the nematodes infect mole crickets, the pests die within 10 days. These parasites work best when applied in late September and October, when adult mole crickets are abundant. In the spring, especially March and April, before the adults mate and lay eggs, is the next best application time, as it will prevent them from easily multiplying.
Another natural enemy of the mole cricket is the tachinid fly, the crabronid wasp or the larra wasp, which lays its eggs on the mole cricket where the larvae feed off the mole cricket’s blood. When the wasp matures, it kills and eats its host. These types of wasps do not sting humans and can be easily attracted to a yard by planting button weed and partridge peas. They are solitary wasps, so there’s no chance of accidentally stumbling on a nest.
Homemade traps made with molasses are another organic method of control against mole crickets. Place glass jars in your vegetable garden in areas where mole crickets are a problem. Push them into the soil so the top of the jar is at the same level with the ground. Fill each jar halfway with a mixture of one part molasses and 10 parts water. The mole crickets will be attracted to the molasses and will fall in the jar and drown. Keep an eye on the traps, and clean and refill them as needed. You can also use honey or beer, instead of molasses, as it has the same efficiency.
You can also make sticky traps at home and use them to fight these pests. By cutting rectangle pieces of thick paper and paint them on one side with a mixture of corn syrup and water, you will have a sticky trap available and easy to use. Place such traps in the ground in your garden and monitor them from time to time. Keep in mind that such type of traps can also catch different other insects, not just the targeted mole crickets.
Placing floating squares of yellow plastic in a pool or hanging them above a bucket of water also works as a bait for mole crickets. When they stop to investigate, they fall into the water and drown.
To repel mole crickets, you can plant different types of flowers, such as marigolds, calendula or chrysanthemums between your vegetable crops. You can also spread out branches of coniferous trees (spruce, pine, fir) between potato beds, especially after their flowering, or stick freshly chopped stakes or branches of aspen or alder, 2-4 cm thick and always with bark on them, in the soil. It is recommended to do this and stick the branches at a depth of 25-30 cm and at a distance of 1.5-2 meters from each other and replace them as they dry up. It is also recommended to water the spots marked with mole cricket trails with an infusion of onion husk and onion waste, plant a seedling or some pounded garlic into a hole, as it will give off a deterring smell that will make the mole crickets relocate.
Chemical control methods
Mole crickets are easier to control when damage is less evident, which means that the eggs are not laid yet or the nymphs are still young, and have not managed to do much damage. After testing the soil for their presence, with a mixture of soap and water, you can proceed in applying insecticides, to make sure the infestation does not develop and spread.
The key to a successful mole cricket treatment is timing. Applying methods of control soon after the eggs have hatched will help you avoid extensive damage caused later in the year. Even though it will be more difficult to observe their presence when they are small and young, it is better to face these pests then, as when they reach adulthood, usually during spring, they will me harder to control. Most people attempt to kill mole crickets when they first appear, as the first sightings are in late winter or early spring, but the most destructive stage of the pest is the nymphal stage. That is the stage when they will devour the lawn and roots of the plants in your garden. The best time of fighting them and applying insecticides is when the mole crickets are small. Depending on the area you live in, mole crickets have a certain time when they lay their eggs and when these hatch. When you choose your pesticide, it’s important to find out what is the best time to apply it in your area, in order to kill not only the adult pests you are encountering, but the nymphs, which are the one causing the most damage.
The application itself depends on the exact type of insecticide that you choose, but most should be applied overnight, when temperatures are up to at least 16 degrees Celsius. Late June and early July is normally the period of time when eggs hatch and the population of nymphs increases. As summer passes, they continuously eat and develop inside the soil, damaging the vegetation and becoming harder to kill. Depending on when you are using your treatments, you can choose different types of insecticides. As in the late fall they are actively searching for food to last them over the winter, you can use a bait formulation treatments. These are normaly based on active ingredients such as bifenthrin, carbaryl, imidacloprid, gammacyhalothrin, deltamethrin, permethrin.
Whether they are granular, liquid or in a dust form, insecticides based on these active ingredients can be used with efficiency against mole crickets. No matter what type you chose to apply, make sure you check the label and the instructions, as for some insecticides it is important that the soil has adequate moisture, so the product can penetrate it. On the other hand, for others, irrigation is required after application, not before, or maybe not at all. Keep in mind that even though pesticides might be the most effective way to remove mole crickets from your property, they can also affect the lawn and environment you apply them to, if misused.
Baits are usually effective in the spring, before mole crickets lay eggs; if you do not live in a particularly vulnerable area, one such treatment should be enough to last you an entire year. However, if you already have a severe infestation in place, baits will no longer be useful, and you will have to use sprays. These usually have to be applied a couple of times a season (it is recommended to treat once a month for at least three months), but if you are persistent and maintain a regular schedule, they will be more than effective.
Mole crickets may also occasionally wander indoors, though only by accident. In such cases, all you would need to do is sweep them up and return them outdoors. In such a situation, they are completely harmless; they cannot bite, they cannot sting, and they do not feed on fabric, paper, or any house structures whatsoever. In case of persistent invasion, you may want to take further action and seal (or caulk) cracks, gaps, and any other openings that are small enough to serve as passageways into the house for mole crickets, as well as other occasional invaders.
No matter what type of control method you use, make sure to also make your lawn and garden inhospitable for these pests. It will help in getting rid of the current infestation and will also prevent a future one from occurring. As they are attracted to wet soil, as it makes it easier for them to burrow through, make sure your do not provide them with the wet conditions they like. If it is not necessary to water your lawn or garden due to the application of an insecticides, as mentioned above, it is better to find an effective way of watering it, without soaking up the soil. By making sure the soil is not too wet, you not only avoid the development of future mole crickets, but other pests as well, such as mold or fungus.
You can also check or related article about ways in which you can ‘Prevent infestation with Mole Crickets’, should you wish to find out more about preventive measures and how you can avoid an infestation.