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32 May/June 2015 Landscape and Irrigation www.landscapeirrigation.com LANDSCAPE AND TURF MAINTENANCE growth regulator effects. If you use Azatrol, the product is not organic because this formulation uses synthetic emulsifiers and stickers in the formulation. However, if you use NeemAway, the product uses natural surfactants and stickers and it has OMRI certification. Being "natural" and/or "organic" does not mean that the chemical is low in toxicity. Rotenone, a botanical insecticide de- rived from a tropical plant's roots, was considered organic until testing found that it was a relatively toxic general metabolism inhibitor. It is now banned in Europe and the United States for insect control. WHAT WORKS: BIOLOGICAL CONTROLS As previously stated, the insect parasitic nematodes are probably the best of the true biological controls for use in turfgrass, but expensive. There are numerous species and strains on the market, but I can distill them down to two groups — nematodes that are best to control caterpillars and nematodes that are best for soil- dwelling pests like billbug larvae and white grubs. Nematodes in the genus Steinernema are general parasites that are very good at finding sod webworm and cutworm larvae. When billbug larvae are near the soil surface, Steinernema species can also be effective. For white grubs, nematodes in the genus, Heterorhabditis are the ones to use. If you are going to use the nematodes, be sure to contact the supplier months before you will need to control your target pest. Be sure to ask what strains they recommend for cat- erpillars, billbugs or white grubs. Determine when you will need the nematodes and the size of area you will be treating. The sup- plier will then gear up to produce fresh nematodes for the time you need them. To get the best efficacy out of the nematodes, use the fresh product within days of receiving it. They can be applied using regular sprayers that deliver 1.5 to 2.0 gallons of spray per 1,000 square feet. Apply late in the day to avoid direct sunlight and wa- ter in immediately after the application. Daily irrigation for the next four to five days will improve the nematode performance. Milky disease (Phaenobacillus) of white grubs, the white fun- gus of insects (Beauveria) and green fungus of insects (Metarrhi- zium) are all available as commercial biological control products. None have been shown to consistently achieve acceptable levels of control (i.e., greater than 60% mortality), so don't waste your time and money. In fact, all these diseases are readily found in turf insect populations, but the diseases never kick off into epi- demic levels, even when enhanced by additional applications. WHAT WORKS: BIOBASED CONTROLS As previously stated, none of the EPA 25b (minimum risk pesti- cides) have been shown to be effective at controlling turfgrass in- sects in the field. This would include products that contain clove, peppermint, cedar oils or garlic or pepper extracts. Biobased pesticides with demonstrated efficacy include mi- crobials (Bt delta-endotoxins, spinosyns, and Chromobacterium extracts), and botanicals (azadirachtin and natural pyrethrum) Bt 'kurstaki ' and 'aizawai ' strains are active against caterpillars and there are formulations that can effectively kill sod webworm, A masked chafer larvae that has been killed by the green fungus of insects. A billbug adult killed by Beauveria, the white fungus that attacks insects. This masked chafer larva was killed by Heterorhabditis nematodes that nor- mally turn their victims a reddish color.