Diseases
Research on biorationals for control of nematodes
Nematodes are causing increasing problems on golf course greens (read more here), and, with the cancellation of Nemacur (fenamiphos), there are few effective products available for their control. For this reason, we conducted a field study on the efficacy of several different biological control agents for control of nematodes — particularly the root knot nematode, Meloidogyne. We found that:
- An experimental product based on the beneficial bacterium Bacillus firmus had the best results, causing significant reductions in root knot nematodes (RKN) without any associated phytotoxicity
- The amino acid methionine also caused reductions in RKN, but also caused significant damage to bentgrass at the rate tested
- The other products tested included Biofence, which is based on ground mustard plant tissue) and Inoculaid (a mixture of beneficial bacteria). Neither of these products had an impact on nematode populations
Bottom line: Bacillus firmus, which has been shown in previous studies to have potential as a nematicidal agent, showed promise in this trial for control of root knot nematode. Further work is needed to confirm this, and to identify optimal use patterns. This product, which is under development at Bayer Environmental Sciences, is not yet available for sale, but if research continues to confirm its promise, we hope expect to see it made available very soon.
Project title: Biorational products for nematode control
Principal investigators: Larry Stowell, Ph.D., CPAg and Wendy Gelernter, Ph.D., PACE Turf LLC and Michael McClure, Ph.D., University of Arizona
Cooperator: Troy Mullane, Rancho Santa Fe Farms Golf Club, Rancho SAnta Fe, CA
Sponsor: PACE Turf LLC
Click here for the full report (206 KB pdf)
Evaluation of nematode thresholds and turf damage
Summary:
A study conducted in 2007 at La Jolla Country, with cooperator and golf course superintendent John Pollok, investigated the relationship between nematode counts and turf damage. After surveying samples from all 18 bentgrass greens for nematodes, we found that there were three different species present —ring nematode Criconemella, root knot nematode Meloidogyne and spiral nematode Helicotylenchus. However, none of these nematodes, even when occurring in high numbers, was associated with turf damage.
The full print version of the report, "Evaluation of nematode populations and nematode damage" is now available.
The bottom line? Don't treat for nematodes unless you are really sure that they are the source of your turf damage. Consult this PACE Update on nematodes and turf for information on how to identify nematode damage at your location.
Principal investigators: John Pollok, La Jolla Country Club, and Larry Stowell, Ph.D. and Wendy Gelernter, Ph.D., PACE Turf
Posted 9/15/08
Using virtual irrigation to forecast disease
Poster presentation at the 2008 American Phytopathological Society meetings, July 26 - 30, Minneapolis, MN.
Authors: Larry Stowell and Wendy Gelernter (PACE Turfgrass Research Institute) and Frank Wong and Chi-Men Chen, University of California Riverside
Click here to view the poster (130 KB)
Summary: Recent research suggests that soil moisture impacts the severity of turf diseases such as anthracnose caused by Colletotrichum cereale, Pythium root dysfunction caused by Pythium volutum, gray leaf spot (GLS) caused by Magnaporthe grisea and brown ring patch (BRP) caused by Waitea circinata var. circinata. The virtual irrigation audit, a simple computer model that predicts the size and location of both wet and dry areas on golf course turf, was designed to provide diagnosticians and turf managers with a precision turfgrass management tool for disease and soil moisture management. In this study, the virtual audit was successfully used to describe the occurrence of GLS and BRP on golf course turf.
