Golfdom, March 2018

TODE TROUBLE Continued from page 20 and university and industry experts before deciding whether to apply a nematicide In the last two years three new nematicides Divanem abamectin Syngenta Indemnify fluopyram Bayer and Nimitz fluensulfone Quali Pro have been introduced into the turf market With a year or two of experience with these products we talked to experts at each company to learn more about them Syngentas Divanem Divanem has been well received by superintendents and it was no surprise since superintendents asked for the product in the first place says Lane Tredway Ph D Syngenta technical services manager and turfgrass pathologist Tredway explained that Billy Crow Ph D nematologist at the University of Florida worked with Avid abamectin Syngenta which at the time was labeled for insect control in ornamentals on turf and found it provided effective nematode control Once superintendents saw the results of Crows research they asked Syngenta to make abamectin available for turf Syngenta responded by making Divanem which is abamectin formulated specially for turf use Divanem is a restricted use pesticide With todays new nematicides it pays to be proactive Tredway advises suggesting superintendents sample regularly and apply Divanem while there is active root growth and before the turf declines Superintendents can use Divanem as a rescue treatment but it requires multiple applications and requires favorable weather conditions and cultural practices to stimulate turf recovery The most successful use of Divanem is as part of a preventive program that includes multiple applications of nematicides with different modes of action Tredway says Think of a strategy similar to controlling fungal diseases season long and with multiple active ingredients Applications are especially important during times of active root growth which is when nematodes are most active Find examples of season long programs using Divanem at GreenCastOnline com Programs Tredway also encourages superintendents to consider applying Heritage azoxystrobin Syngenta or Velista penthiopyrad Syngenta fungicides in a tank mix with Divanem plus a soil surfactant to control root diseases This along with controlling nematodes improves turf performance Because all the products need to be watered in for maximum effectiveness the tank mix makes sense Tredway says Always leave an untreated area for comparison when treating with Divanem Nematode populations fluctuate widely during the growing season so relying on nematode counts to gauge success can be misleading Tredway stresses Nematodes numbers fluctuate because of weather and root growth The more roots present the more nematodes present Tredway advises focusing on root growth and turf performance rather than focusing on nematode counts and having an untreated area for comparison makes it easy to judge the effectiveness of Divanem Figure 1 Divanem has broad spectrum activity on root feeding nematodes and controls sting lance and root knot nematodes the most common nematodes in turf In addition to applying Divanem during periods of active root growth Tredway recommends tank mixing Divanem with a soil surfactant and watering in 01 inches immediately after application with 025 inches of water within 12 hours after application Applying Divanem after aeration while aeration created channels are still open helps move Divanem into the soil When used according to the label Divanem has a low impact on the environment It is tightly bound to soil and organic matter so has a low risk of leaching but underscores the need to water in Divanem Continued on page 24 22 Golfdom March 2018 Golfdom com PHOTO COURTESY OF SYNGENTA Figure 1 Soil cores taken from a Champion ultradwarf bermudagrass putting green in Florida show the root system of an area treated with soil surfactant only left and an area treated with Divanem and a soil surfactant right applied Aug 23 and Sept 21 2016 Samples were collected on Oct 25 2016 Lane Tredway NEMATODE POPULATIONS FLUCTUATE WIDELY DURING THE GROWING SEASON SO RELYING ON NEMATODE COUNTS TO GAUGE SUCCESS CAN BE MISLEADING LANE TREDWAY PH D