Grub Guard Predatory Nematodes (OMRI Listed)

These nematodes are refereed to as thoroughbreds because unlike most beneficial nematodes which are raised on a dog food-like substance, Grub Guard nematodes are raised on insects (in vivo). Although this process is more costly than rearing on artificial media (in vitro), we believe this technique produces a much more aggressive strain.

Unlike other nematode producers, Grub Guard uses two different strains of nematodes because of their different abilities. Steinernema sp. are shallow soil dwellers that occupy the top 1-3 inches of soil. These nematodes are ambushers and attach themselves to soil particles near the soil surface waiting for prey. Heterorhabditis sp. burrow down as deep as 5-6 inches, offering a secondary barrier to grubs that are emerging from or submerging into winter soil depths. Because Heterorhabditis sp. reside deeper in the soil, they are less susceptible to drought conditions. Heterorhabditis sp. are hunters that follow grub exudates through the soil .

Both species act by invading grub or larval bodies through orifices, such as the mouth, anus, or spiracles, where they release bacteria that are symbiotic to them but deadly to the larvae. The bacteria multiply and produce enzymes that destroys the hosts protein.

The grubs normally die within 24 to 48 hours. Grub Guard nematodes soon begin reproducing the next generation of offspring, which mature and reproduce another generation, which then reproduce a third generation. The SF nematodes require both a male and a female to reproduce but the Heterorhabditis sp. can develop into a hermaphrodite and reproduce asexually. Steinernema sp. cycle in about 7 to 10 days from infection to emergence and Heterorhabditis sp. takes about 12 to 15 days. By this time the food supply from the host has been depleted and Grub Guard nematodes emerge in numbers that will often exceed 100,000. All of these hungry, microscopic juveniles go off in search of new larvae for new prey.

Grub Guard nematodes are shipped alive and should be released into a thoroughly moist soil or growing media as soon as possible. There is no advantage to ordering enough nematodes to last an entire season. They can be stored for a short period of time (about 1 month) under refrigerated conditions (40-50 degrees F) but the small sponge that Grub Guard nematodes are shipped in must be kept damp and the package should be left open to allow fresh air to enter. Add a few drops of water if the sponge appears to be drying out. When mixing, the ideal water temperature is between 65 and 80 degrees F. DO NOT USE HOT WATER. Grub Guard nematodes are nocturnal and preferably released in the evening or at night. Rainy and overcast days are by far the best conditions to release these predators.

Grub Guard nematodes will survive at soil temperatures between 32 and 90 degrees F. However, they are most aggressive at temperatures between 65 and 85 degrees. They cannot survive at soil temperatures above 90 or below 32 degrees F. Reapplication may be necessary if the soil reaches beyond these extremes. Grub Guard nematodes are very sensitive to sunlight. After 7 minutes, exposure to ultraviolet light will sterilize the nematodes. Therefore, it is crucial that Grub Guard nematodes be watered into the soil quickly and thoroughly. Irrigate if necessary before applying to ensure that the environment is sufficiently moist. Applications in the early evening or early morning are recommended. Grub Guard nematodes can be applied through any modern liquid delivery systems and can withstand pressures up to 300 p.s.i. Filters should not be smaller than 50 mesh (i.e., 50 openings per linear inch or 0.020 sized opening). Optimum soil moisture for nematodes is ~15%.

Like most beneficial organisms, Grub Guard nematodes should be applied in anticipation of a grub problem. The "ounce of prevention vs. the pound of cure" rule is most appropriate with any predator insect. Concentrate the Grub Guard nematodes where problems are most likely to appear.

1) Grub Guard can be soil-applied using shank, cultivator, spoke-wheel applicator or root feeder/injector.

2) Apply Grub Guard in 30 - 100 gallons of water per acre.

3) Shank: Apply as a trickle behind each shank at a 2 - 4 inch depth followed by a press wheel to cover opening. 

4) Cultivator: Apply as a spray immediately in front of a rolling cultivator. Incorporate to a 2 - 4 inch depth. 

5) Spoke-wheel: Double spoke-wheels should be placed 6 - 8 inches apart and centered on the bill. Inject at a 2 - 4  inch depth.

6) Root Feeder: Soil inject to depth of plant roots, 2 -8 inch depth

Ground Spraying 
All Surface Spraying Equipment 
1) Apply Grub Guard with a minimum of 100 gallons of water per acre.
2) Soil should be moist before beginning application.
3) Soil temperature should be between 35 - 85 F.
4) Follow post-application irrigation instructions.

IRRIGATION REQUIREMENTS 
1) Prior to application, ensure that soil is thoroughly moistened to the full depth of the root zone.
2) Surface application: Following application of Grub Guard, immediately irrigate with 1/4 - 1/2 inch of water. 
3) Subsurface application: Irrigate field no later than 3 days following application.
4) For maximum Grub Guard performance, maintain adequate soil moisture for 21 days.

Many pesticides are toxic to nematodes.