How To Use Predatory Nematodes

For best results apply predatory nematodes in the late afternoon or early evening, because they will be killed if exposed to direct sunlight. Use this material only when you detect the presence of the larvae or grub of a pest insect; usually in the late spring and early fall for most insects.

The soil should be moist at the time of application and lightly watered immediately after application. After application, regular watering of the treated area will provide sufficient moisture. The best soil temperature for getting the most effective results is a range between 55&temp;F and 85&temp;F. In best conditions of moisture and temperature, predatory nematodes should be effective for 6 to 8 weeks.

Mixing of concentrate - To assure maximum effectiveness, use all of the mixture with the nematodes within 3 hours of preparation.

Nematodes must be applied directly to the soil around the target plant or in the target area. Do not spray nematodes on the leaves, branches or stalks of plants unless you are going after borers. The area covered or controlled will vary from product to product.

There are 3 ways to apply the Beneficial Nematodes (BN)

USE NEMATODES IN A TOPDRESSING: With this technique you will usually mix the entire contents of the container with the amount of water specified in the instructions. Stir well and let stand for at least an hour. Stir again and add 5 to 6 quarts of vermiculite or Canadian sphagnum peat moss to make a slurry.

Apply the slurry directly to affected areas. For new plants or transplants, apply around roots. Apply after sundown because sunlight will kill the BN. Water thoroughly after application because BN travel best in moisture.

APPLY NEMATODES BY SPRAYING: Mix the entire contents of the container with the amount of water specified in the instructions, stir well and let stand for at least an hour. Water the area to be treated before application. Use a watering can, hose sprayer, or pump sprayer. Always use the coarsest or highest rate setting to reduce damage to the BN.

Stir the mixture again and pour into the sprayer, filtering out the carrier as you go (Use a kitchen strainer or a piece of window screen.) Add the left over carrier to your soil. Always agitate the water while spraying and before pouring because the BN sink to the bottom.

Apply after sundown because sunlight will kill the BN. Water thoroughly after application because BN travel best in moisture.

APPLY NEMATODES BY INJECTION: Mix the contents of the container with THE amount of water specified by instructions. Stir well and let stand for at least an hour. Strain out the carrier (use a kitchen strainer or a piece of window screen), use the carrier in the soil, and let the strained liquid stand for another hour. This allows most of the BN to sink to the bottom. Pour away the top water, saving the last pint.

Use an eye dropper or squeeze bottle to inject about a tablespoon of liquid into the burrow, the borer hole, or the blossom harmed by the target pest insect. Seal the hole if possible. You can also find a kind of hypodermic needle that is sold in gardening catalogs for injecting insecticide into stems and blossoms of plants.

Remember, If you are trying to control borers then you want to try to have the nematode solution make contact with the opening used by the borer(s). This technique is still in its infancy, so experimentation may be needed. There are syringes available for applying pesticides into the holes of borers. These devices should work well with nematodes.

What Not To Do
Do not mix predatory nematode products with other fertilizers or chemicals. In fact you should allow a week between application of fertilizers or other chemicals and the application of a predatory nematode product. You may apply either the fertilizer of the predatory nematode product furst, but wait a week between applications.

Do not use diatomaceous earth on the same site as you use predatory nematodes. D.E. will harm predatory nematodes.

Shelf Life and Safety
Most products containing predatory nematodes need to be kept refrigerated, but not frozen. The best temperature range is 43&temp;F to 47&temp;F. While it is best to use the product as soon as possible, nematodes will survive for 6 months in that condition. You can store predatory nematodes, properly packaged at room temperature for up to 3 months.

Safety For People
Because predatory nematodes are found naturally in the soil, products containing these micro organisms are not modified in any way so the material is exempt from EPA registration. This material is considered absolutely non-toxic to humans, mammals, fish, and birds.

Safety For the Environment
Persistence is a measure of the length of time it takes for any insecticide to biodegrad or change its chemical identity, becoming a compound or material that is harmless. Half life is a measure of one half of the period it takes for the insecticide to break down into a harmless form. Most predatory nematodes will die after 4 to 6 weeks because there are no more grubs in which to lay their eggs. The remaining nematodes will survive until frost with a very few making it through the winter. The number of beneficial nematodes surviving to next season is not going to be high enough to have any impact on pest insects next year.

Impact On Soil
Predatory nematodes will not harm earthworms.

Impact On Birds
If a bird eats a grub infected by predatory nematodes, it will not in any way be harmed.

Impact On Butterflies
If predatory nematodes come in contact with any butterfly larvae in the soil, they will kill them. However, you should not be using this material over your entire property so the butterflies with soil-borne larvae should not be wiped out. Few butterfly larvae reside in the soil under turfgrass.

Impact On Honeybees
Honeybees are in no way affected by predatory nematodes.

Impact On Beneficial Insects
Most beneficial insects do not have larvae residing in the soil, so they are safe from predatory nematodes.