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Lawn Care 2 — Problem Intervention
By Sarah Coulber
By following some basic lawn care practices outlined in Lawn Care, Part 1 —Maintenance, you will prevent many problems. If you do encounter a problem, however, here are some solutions that might work for you:
Insects
If an infestation does occur and you need to act quickly, the following tips will help you identify the problem pest accurately and use appropriate organic controls:
Chinch bugs
Checking to see if you have a chinch bug problem
These small red bugs with a white band across their backs can damage lawns by sucking the juice from grass. The black and white winged adults may also do damage. A sign of their presence is brown or yellow grass next to healthy grass or pavement. To determine if chinch bugs are the cause of your lawn woes, take a can with both
ends cut out or some wide tubing, push it into the soil where you suspect the chinch bugs are feeding and fill with water. Chinch bugs will float up within minutes.
Eliminating them
- Follow the guidelines for a healthy lawn in Lawn Care, Part 1 — Maintenance and you will significantly decrease the chances of chinch bug infestations. Pay special attention to fertilizing because too much nitrogen can cause excessive green growth and weaken the plant.
- Chinch bugs like dry conditions so water deeply in the spring, the time when they lay their eggs and the young hatch. The moist soil, according to Rodale Organic Gardening Basics: Lawns, will help a “naturally occurring fungus keep chinch bugs under control.”
- Keep compacted soil and thatch to a minimum to decrease places for these bugs to find shelter. A normal layer of thatch is not considered a problem when you have healthy soil full of beneficial micro-organisms . If you happen to cut very long grass and end up with a thick layer of thatch, you may wish to mow again to break up the thatch, or rake it to put on your compost pile, to deter these bugs from sheltering in it.
- The Environment Canada fact sheet, Alternatives to Pesticides — Answers to lawn care problems, suggests spraying the problem area “with soapy water once a day for 10 to 14 days, or with a solution of a handful of wood ash and lime in eight litres of water. Spread a flannel sheet over the treated area and, in less than half an hour you should find bugs attached to the sheet, ready for disposal.
White grubs
Checking to see if you have a white grub problem
These are the larvae of scarab beetles (Japanese, June and Chafer beetles to name a few), which feed on the roots of grass and other plants. While a few in your lawn is normal, you know you have a problem when you find big yellow or brown patches of grass and a spongy sensation when walking on it. If you were to dig the area, it would lift up easily because the roots have been chewed up, and several white grubs with dark heads curved into a “c” shape would be apparent. If you find 10 or more grubs per square foot (108 per square metre), you could have a white grub infestation.
Eliminating them
- Parasitic nematodes are living organisms of microscopic scale that will kill the unwanted grubs. Because the nematodes are alive, they must be handled with care. Read the instructions on the package very carefully. As a general rule, keep them cool at all times until they are moistened just before application. Do not let them sit in water and do not expose them to light (UV). Water the grass before application and then spray the nematodes on the lawn with a sprayer on an overcast day, or in the evening when the temperature is at least 15˚C, and keep the soil moist. Nematodes need to be placed where the grubs are and should be applied across the whole lawn, rather than in spot applications. You will have more success if the nematodes are applied when the grubs are small. This is often in the spring and late summer, but double check the grub you are dealing with and its life cycle to be sure.
- Strengthen grass roots to better resist grubs. Overfertilizing, as with quick release fertilizers, can create soft, weak roots. Use natural fertilizer for slower, steadier growth all year. Mowing the grass to a higher level (don’t cut it too short) will also encourage a deep strong root system, as will deep infrequent watering. Avoid fertilizing in the summer because it could stress the plant at a time when lawns in most parts of Canada tend to go dormant or semi-dormant.
- Avoid over-watering the lawn in the spring when female adults are looking for moist grassy areas to lay eggs. If you do water, remember to water deeply and infrequently, which encourages the water to go deeper into the earth and allows the top layer to dry out in between waterings. Also, refrain from watering in the summer after the grass has gone dormant to reduce the survival of eggs and larvae.
Sod webworms
Checking to see if you have a sod webworm problem
Signs of these insects are dead patches of lawn appearing in the late spring and on into the summer. Earlier in the spring, you can also watch for white moths that fly over the lawn preparing to lay eggs. The larvae live in underground tunnels and come out at night. You may spot them at night with a flashlight, as they go about cutting grass blades and bringing them into their tunnels.
Eliminating them
- Try pouring a soapy solution on the affected area — about 30 millilitres (two tablespoons) of liquid detergent to 3.75 litres (one gallon) of water, according to Rodale Organic Gardening Basics: Lawns. This should bring the insects out of their tunnels to be collected and disposed of.
- Another recognized method is applying Bacillus thuringiensis (BT) two weeks after spotting adult moths hovering above your lawn.
- As with other pests mentioned, you should eliminate compacted soil and thatch where the pests can shelter, and bare spots where the pests can flourish.
Furry Visitors
- Raccoons, skunks and moles can damage your lawn by digging. Chances are, however, that they are digging to get at the grubs in the soil. Eliminate the grubs (see Insects above) and you will deter these furry critters and improve the health of your lawn. While bothersome, the damage from raccoons, skunks and moles may be far easier and cheaper to manage than dealing with the grubs alone.
When these mammals have finished their feast, they will likely move on to another good feeding area.
If moles do hang around, they may provide other benefits such as mixing up the soil, which creates a natural aeration as well as bringing mineral-rich soil up to your lawn’s roots.
- If you really can’t live with moles in your garden, try burying a pop bottle in the ground near a hole to their tunnel, with the open top of the bottle sticking out. Passing breezes will catch the lip of the open bottle, producing a sound that will encourage moles to move their homes to the bottom of your garden or beyond.
Weeds
Weeds are a good indicator of what you can do to improve your soil and your lawn’s health. Even a garden full of dandelions can be radically improved without resorting to chemicals. Try these ideas to help achieve a tolerable balance between lawn and weeds, and visit Lawn Care, Part 1 — Maintenance for more information.
- Keep your lawn dense. Open areas, caused by unhealthy weak grass, insect problems or adverse weather conditions, are an invitation for weeds. Overseed (link to Lawn Care, Part 1 — seeding section) to make it harder for weed seeds to germinate.
- Check the pH of your soil. While many weeds are opportunists and can tolerate a variety of conditions, most grasses find a pH of 7.5 a little high. Check your local garden centre to get a soil testing kit and natural products such as lime to help balance the pH. Many gardeners find that sprinkling and gently raking in compost is a great way to improve the soil. Try leaving grass clippings on the lawn, too.
- Get your mower moving. Mow your grass at approximately 7.5 centimetres (three inches) to keep it healthy. Time the mowing with when your weeds are in flower so you can cut them before they have time to go to seed. If need be, mow more frequently to keep cutting off the tops of the weeds. After a couple of years, you will notice a big improvement. When you do spot the odd dandelion, remember that it’s helpful to beneficial insects, such as butterflies and bees, that need nourishment in the early spring and fall when there are fewer flowers.
- Water wisely. Water deeply and infrequently to strengthen your grass plants, preferably 2.5 centimetres a week, in periods of minimal rain. (You can measure how much you have watered by placing an empty tin can (tuna cans work well) on your lawn before you water.)
- Do a little digging when out for a garden stroll. Hand-digging takes time but it’s very effective because you can remove the root. There are devices made to make the job quicker and easier on your back, such as a Dandelion Digger sold by Lee Valley Tools . If you have a big problem area, enlist the help of some friends or family members for a morning or afternoon.
- Depending on how many weeds you have, applying vinegar to the leaves (with a small brush) may be an effective option. The white vinegar sold in grocery stores is likely a five or 10-percent solution. Older, more established plants may require repeated applications or perhaps even higher concentrations of vinegar such as 20 percent. Remember that the strength of the vinegar may harm beneficial insects, so apply directly on the weed leaves with a brush to prevent dispersing into the soil. Visit the USDA Agricultural Research Service to find out how researchers dealt with some problem weeds.
- To stop weed seeds from germinating, try an organic pre-emergent, which inhibits the growth of newly sprouting seeds, killing the plant before it becomes a problem. An example of this is corn gluten meal (CGM), which releases a protein whenever it is moistened, inhibiting the growth of plant roots, which kills the plant by cutting off its supply of water and nutrients. CGM is used mainly for dandelions and crabgrass, as well as curly dock, plantain, lamb’s quarters, pigweed and knotweed.
CGM is also used as a fertilizer and, providing a product is mainly CGM, it is an all-natural product that will not burn your lawn.
Where to get it: CGM is also used as livestock feed, so look for it at a farm feed store near you. Some health food stores now also stock it. This product may be more costly than other methods for killing weeds, but it is reputed to be very effective if used correctly, and it has a cumulative effect over time. Meanwhile, you are also providing a natural fertilizer that will help create a lush green lawn.
What kind to buy: There are powdered, granular and pellet forms of CGM. The powder or granules may be better as the pellets might be eaten by hungry birds and other critters. The powder, on the other hand, can blow away or get caked up. If you use the powder, water it with a fine mist spray and, if it cakes up, rake it in a bit. Make sure that the product you buy is mainly corn gluten meal, because some products have added nutrients that may enhance the fertilizer effect, but reduce the ability to inhibit weed seeds.
When to apply: Use CGM when seeds are likely to germinate. Do not apply too early because the soil organisms will break it down, rendering it ineffective as weed control, although it will still work as a fertilizer. CGM will work on all seeds so do not apply on a windy day in case it travels to areas where you have seeds that you do want to sprout. Also, don’t apply at the same time that you apply grass seed.
How to apply: Apply five to 10 kilograms to an area of 100 square metres, and more on bare ground because there will be more light and less competition for weeds to thrive. You may find it easier to apply the CGM with a seed or fertilizer spreader. Water it in with a gentle spray to prevent it from scattering and to help work it into the soil. Let it dry but if it is very dry in the days following, you may wish to water it one more time.
Research indicates many weeds can be eliminated in the first year, and the percentage rises with each successive year it is used. Store any unused CGM in a dry place, as moisture will break it down.
WAG Links
Articles
Information on Pesticides
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