Turfgrass management refers to the various cultural practices used to maintain a healthy lawn, such as proper irrigation, fertilization, and mowing. Pest and disease management are just as important as understanding insects. The mole cricket is a troublesome insect pest that causes significant damage to turfgrass in the Southern United States.
In South Carolina, there are three species of mole crickets that occur mainly in the sandy coastal regions. The three main types of mole cricket found in the United States are the tawny mole cricket, the southern mole cricket, and the northern mole cricket. Tawny and southern mole crickets are two types of mole cricket that can have a big impact on how turfs are managed. The northern mole cricket is from South Carolina but barely damages lawns, if at all.
Both the tawny and southern mole crickets are non-native species in the United States. It is believed that these species were introduced into the United States in the ballasts of ships from South America. Mole crickets were first detected in coastal port towns during the late 1800s and early 1900s, such as Brunswick, GA, Charleston, SC, and Mobile, AL. Insects that establish themselves in sandy coastal areas of the southeast spread rapidly.
The most destructive of these to home lawns is the tawny mole cricket. The northern mole cricket feeds on almost exclusively turfgrass roots and shoots. The southern mole cricket Feeds primarily on small organisms in the soil and rarely on the turf itself. In addition to destroying plants by eating them, these insects also tunnel through the soil just beneath the lawn. Tunneling by grubs can damage managed turfgrass, especially golf greens.
Both the tawny and southern mole cricket look like crickets. They have three pairs of legs, three-segmented body parts, and a set of antennae like all insects. They have legs that are good for digging and they look like the front legs of a mole. The tawny mole cricket is a bigger, more robust insect compared to the southern mole cricket. The tawny mole cricket is tan-colored, while the southern mole cricket is a darker brown, almost black. The southern mole cricket has four dots on its head that are light in color. The tawny mole cricket grows to be 1 1/2 – 2 inches long, while the smaller southern mole cricket grows to be 1 – 1 1/2 inches long.
An effective mole cricket management program requires a deep understanding of the insect’s life cycle.
There are two types of mole crickets found in South Carolina, the southern and tawny mole cricket. Both types have similar life cycles. These mole crickets only have one generation per year, which is fortunate. In regions further south, they can have two or more litters per year.
Mole crickets go through three different stages in their lives- eggs, immaturity (or nymph stage), and adulthood. Mole crickets can survive the winter as either an immature insect or adult, from October through March. During winter, they are inactive but if the weather gets warm, they become more active. Tunneling and mound-building can be seen during these warm spells. Mole crickets that spend the winter as immatures will develop into adults during the spring.
As temperatures get warmer from late March into April, adults become more active as they begin to fly and mate. Adult males look for a good place for females to lay eggs; they may go back to the same spot every year. Mole crickets often return to the same areas of the lawn each year because they are attracted to the moist soil.
After finding a suitable location, the male will dig a small tunnel or chamber that has an opening to the surface of the ground. A small mound of soil with a visible opening may appear in the lawn during this time. This is most likely a mole tunnel, which is created when a mole pushes up soil from underground. The mating chamber is funnel-shaped and helps amplify the male’s call to females.
Mole cricket mounds and earthworm mounds may look similar, but there are some key differences. The biggest difference is that earthworm mounds are made up of small, round pellets, while mole cricket mounds look like the soil was pushed up from underneath, with a hole in the middle.
After sunset, male crickets chirp for around an hour to try and attract a mate. Calls that may be heard during warm nights in late March and April.
Once a female has been attracted, the two animals will mate within the chamber. She lays a cluster of around 35 eggs shortly after mating, digging down several inches in the soil. Females usually make 3 to 5 chambers and lay 100 to 150 eggs. A male’s death occurs after he mates, and a female’s death happens shortly after she lays her eggs.
Eggs typically hatch approximately 20 days after being laid. Egg hatching is affected by soil temperature, with warmer temperatures causing eggs to hatch earlier, and cooler temperatures delaying hatching by up to a month.
The immature mole cricket, or nymph, is about ¼-inch long after it hatches from its egg. As the cricket grows, it will periodically shed its outermost layer, similar to the way a snake sheds its skin. The younger nymphs do not have any wings but eventually develop wing pads as they mature. They go through six to eight moults during the immature stage.
The immature growth stage typically occurs from mid-May through July. The timing of this stage is dependent on temperature and may be shifted with changing spring temperatures. Small mole crickets are causing little damage even though they’re feeding. The small size of the cool-season grasses is the reason they are not as apparent when they are growing rapidly and masking any damage that is being done.
Damage to lawns from mole crickets begins to occur in late August to October as they mature and begin to tunnel and feed. Mole crickets are more active and cause more damage when the weather is warm and wet.
By October, mole crickets reach their mature stage. The temperatures in the fall can vary greatly, so activity levels can be unpredictable. When winter temperatures occur, mole crickets relocate themselves further into the soil in order to spend the winter there.
Mole Cricket Management
To effectively manage mole crickets, you must be patient and regularly monitor their activity. It is not possible to simply apply an insecticide and be finished with management. Management of mole crickets requires timing control measures and good cultural practices to be successful. It is important to keep the nutrients in the soil balanced by testing it regularly and adding the appropriate fertilizers and lime. Be sure to mow the lawn at the appropriate height for the type of grass you have, and water it accordingly depending on the time of year, temperature, and soil type.
The level of effort required to manage mole crickets infesting a turfgrass area is dependent on what the turfgrass is being used for. A golf course putting green that requires a smooth, blemish-free surface with no mole cricket activity will need intense management. Slightly more mole cricket activity can be tolerated on sod farms and areas used for sports, such as football, baseball, or soccer fields. Lawns that are commercial or home can put up with the most mole cricket activity. The management level should be based on the specific situation and how much damage to the turfgrass is acceptable.
How to Use Beneficial Nematodes for Pest Control
What are beneficial nematodes?
Beneficial nematodes are microscopic segmented roundworms that occur naturally in soil around the world and are beneficial to plant growth. There are more than 20,000 nematode species in total, however the ones used for pest control are entomopathogenic nematodes, which are also known as insect-parasitic nematodes. These nematodes come from the families Steinernematidae and Heterorhabditidae.
The nematodes enter the soil-dwelling pests through orifices in the skin, including the mouth or anus. Once the nematodes are inside the pest, they release a bacteria that poisons the host and breaks down the host’s tissue for the nematodes to eat. The host insect dies within 48 hours.
The nematodes reproduce by laying eggs inside a host’s body. The young nematodes hatch and then feed on the host’s tissue until they have consumed the whole host. Then, hundreds of thousands of infective juveniles leave the initial host and move on to new hosts, continuing the process until there are no pests left.
How to apply beneficial nematodes
What you’ll need
- Beneficial nematodes (widely available at garden centers and online)
- Watering can, hose-end sprayer, backpack sprayer, or pump sprayer
- Large bucket
Step 1: Wait for the right time
benefical nematodes are living creatures that can be killed by extreme heat or UV rays. The most effective time to apply beneficial nematodes is early morning or evening when the sun is low and the soil is cool. It is best to apply sunscreen on a cloudy day in order to reduce exposure to ultraviolet (UV) rays.
The best time to apply nematodes depends on the pest you’re trying to target. To find out what time of year your target pest lives in the soil, learn about its life cycle. Applying beneficial nematodes is most effective when targeting soil-dwelling pests.
Do not buy beneficial nematodes too far in advance because they do not last long. Nematodes can be stored in a refrigerator for a couple of weeks to a month. If you mix beneficial nematodes with water, you can’t store them.
Step 2: Aerate and moisten the soil
Nematodes move through your soil to find their prey (the target pest) by using the water that is in the space between soil particles. To be effective, nematodes must be able to move through the soil, which means the soil can’t be compacted and it must be moist.
Aerating your lawn or garden before applying nematodes can be especially beneficial if you have heavy soil or compacted soil. Aeration of your lawn loosens the packing of the soil allowing for root growth and expansion. This in turn also increases the activity of beneficial soil microorganisms and results in a healthier lawn.
This will help the nematodes penetrate the soil and get to the grubs. Apply water to the desired area before applying nematodes in order for them to better penetrate the soil and reach the grubs. Water the soil until it is damp, but not so much that there is water pooling on the surface. You don’t want to drown your grass or plants. The moist soil will provide ideal conditions for the nematodes to travel, as well as keep the soil temperature lower, which is beneficial for nematode health.
Step 3: Mix the nematodes with water
To make a large amount of slime, start by filling a bucket with filtered water from your sink or refrigerator door. You can use hose water if you purify it with a water filter. Nematodes must be mixed with filtered water to prevent chlorine from killing them.
depending on how they are packaged when bought, the nematodes have to be mixed with water Nematodes are typically found in a sponge, in dry granules, or in powdery clay. These are the different ways to mix the nematodes, and both are very simple:
- If nematodes come in granules or clay: Dump the material into the bucket of water and stir using your hands or a handy tool, utensil, or, well, a new paint stir. The granules or clay should dissolve in the water.
- If nematodes come on a sponge: Hold the sponge underwater and squeeze it several times to release the nematodes into the bucket.
A good amount of nematodes to use per gallon of water is around 1 teaspoon, but the amount you use can be more or less depending on the severity of your pest problem. If the nematodes you purchase come with directions, be sure to follow the instructions regarding how much water to use. If so, always follow the instructions on the package.
Spray or sprinkle the nematodes onto your lawn and garden.
To make a mixture of water and nematodes, fill your watering can or sprayer with water and then add nematodes. The openings of the spreading device should be wide enough (at least ½ millimeter) for the nematodes to get through.
Spray or sprinkle the nematodes across the area you want to treat, either your whole lawn and garden or a specific area ridden with pests. Try to spread the water and nematodes as evenly as possible. If you don’t shake your watering can or sprayer, the nematodes will sink to the bottom.
Step 5: Keep the soil moist
As we already mentioned, nematodes need a moist environment. After applying the nematodes, water the soil more frequently than usual for 10 days to help the nematodes get established. Water the treated area lightly every three or four days during this time.
You should water your grass and plants frequently for the first 10 days, but be careful not to use too much water or you could drown them. A light sprinkling of water is all that is needed to keep the soil moist and cool for the nematodes. You won’t need to water if it rains.
Step 6: Reapply as necessary
At least one more application of beneficial nematodes should be made after the first application. It is recommended to wait around a week to ten days to before applying nematodes a second time in order to achieve the best results. This second application of the product replenishes the population of the desired organisms and ensures you don’t miss any spots.
The target pest population should decrease significantly after two weeks. If the problem persists, keep reapplying beneficial nematodes every 7-10 days until the pests are gone.
It will take about two weeks for a noticeable decrease in pests, but beneficial nematodes kill individual pests within 48 hours. Nematodes need time to consume one host, reproduce, then move on to the next one and repeat the process for each pest.