Guidelines for Improved Performance of Movento as a Nematicide, updated 1-11-11
Michael McKenry, Nematologist UC Riverside
During 2010 our research effort provided additional performance and yield data for Movento applied to perennial crops.
Nematicidal Performance- At this time we can confirm that a single application of Movento can reduce populations of plant parasitic nematodes by as much as 50% over a period of 5 to 6 months. Where drip is the method by which the field is irrigated expect best nematode control following foliar applications of Movento to occur in roots located beyond the wetted front. Whether applied in spring or fall, 4oz/acre is optimal for 5 to 6 months for most nematodes species. Control of ring nematode or Xiphinema index requires 6.25 oz/acre. Control of phylloxera on grape has required 6.25 oz/acre to obtain 50% control for 4 to 5 months. Our experience thus far is that application rates higher than these optimal rates do not improve the level or longevity of nematode control.
Repeated Applications appear Problematic- Nematodes are most damaging when soil temperatures exceed 60F at the one foot depth. Expect 6 months of plant damage possible in cooler coastal climates; 8 months in central valley regions and as much as 12 months in desert regions such as Coachella Valley. This concept in mind, we chose to make treatments in both spring and fall to provide a full year of nematode control. We were able to expand the period of 50% nematode control out for as long as 2 years by making 4 treatments within that timeframe. Unfortunately, repeated treatments of Movento, particularly several years of treatment at rates of 6.25 oz/ac, have not provided the yield improvements one would expect. Repeated treatments at 4 oz/ac (= 8oz/ac/yr) performed better than the higher rate but there still appeared to be a shortcoming. Basically, Movento is providing nematode control adequate to improve fruit quality and increase yields by 10 to 20% following a single application but not when several applications are made each year. Repeated treatments have lengthened the duration of pest control without providing anticipated yield improvement.
New Directions- A single annual treatment of Movento at application rates and timing adequate for control of above-ground pests can provide below-ground pest control if there is attention to avoidance of irrigation for 9 days after treatment. Its successful use is that simple. Movento can provide a nematode control platform onto which other nematode control products or strategies can be attached. Our research direction has changed. We need to evaluate other useful nematicidal agents that can be used in conjunction with the use of Movento. Many times these will be springtime treatments but in the case of Bacterial Canker, for example, we might prefer 6.25 oz/ac Movento applied in the fall. In one grape trial Pasteuria nsp has reduced population levels of citrus nematode down to its damage threshold, thus providing a need for a single springtime treatment of 4 oz/ac Movento per year. Where phylloxera is present and damaging the greatest value from Movento might be 6.25 oz/ac applied once in early June. Yes, growers must also be concerned about reduced application rates relative to above ground pest control whether they are the target or not.
Guidelines for Improved Performance of Movento as a Nematicide, 10-15-09
Michael McKenry, Nematologist UC Riverside
Nematicidal performance of Movento can be influenced by numerous factors. After three full years of study with Movento on perennial crops the following factors need consideration as Movento registration expands to nematode control and growers strive for maximum efficacy against nematodes as well as insects.
Crop- Springtime sprays to grape can be made after May 1 while sprays to walnut should not be made until late May. Fall sprays to grape should be halted after mid October while sprays to walnut could be made as late as mid November. What about other crops?
One way to assess crop differences (if endoparasitic nematodes are present) is to collect root samples at 100 days post treatment and determine if populations are unchanged or controlled (30 to 60% population reductions) when compared to the untreated.
Application Rates- For most nematode species (including root-knot, root-lesion, citrus, and dagger nematodes) optimal nematode control on grapes is achieved at 4 oz/acre which can provide 50% population reductions for 5 to 6 months. These same nematode species treated at 6.25 oz/acre may provide only 10% nematode control when measured monthly over a five to six month period. However, ring nematode is an exception. The application rate for ring nematode on grapes needs to be 6.25 oz/acre to achieve 50% population reductions over a 5 to 6 month period. The nematicidal value of the 4 oz rate against ring nematode can be nil when measured over that same five to six month period. At the present time 4 oz is the optimal treatment rate for nematode control (except ring nematode) but over the years ahead there may be situations and settings where some nematode species appear to increase after several years of treatment at 4 oz. For example, if root-lesion and ring nematode are together in a field and both appear to be responsible for similar damage there may be reason to apply 4 oz in spring and 6.25 oz in fall, or vice versa depending on crop and other timed events that impact the grower. Keep the options open here because insect management must also be taken into account as nematicidal application rates are being considered.
Repeated Applications- We have repeatedly observed the lack of nematicide longevity when re-treatments are too close together. It is as though 4 oz on May 5 cannot be followed by 4 oz on June 5 if nematode control is the purpose of the treatments. We have recently demonstrated that 7 oz to walnut on May 5 followed by 7 oz on July 29 tended to erase our progress with nematode control. More on this next year as experiments continue.
Impact of other Systemics- Presence of other systemic products already within the plant can impact the performance of Movento. In 2006 and 2007 we observed when 14 oz Admire Pro was applied 2-4 weeks ahead of Movento on citrus that there were negative impacts on eventual nematode control. However, our treatment rates in those days were often as high as 24 oz/acre of Movento. More recently we applied Admire to grapes 7 days ahead of Movento and it appeared to enhance the nematicidal performance of Movento. Likewise, we noted that a natural plant material, NatureCur, developed from walnut hulls and having some systemic qualities could interfere with performance of Movento. More recently we observed that NatureCur applied in November could destroy the nematicidal value of Movento applied 7 days later but 5 ½ mo later treatments in those same locations enhanced the nematicidal value of 4 oz of Movento compared to 4 oz without NatureCur.. The point of this commentary is to advise that there are extraneous factors that can directly impact negatively or positively the nematicidal performance of Movento. Studies continue but as this product reaches the hands of growers keep these incidents in mind until these and others are better understood.
Irrigations too soon after Movento spray- In 2008 our recommendation was to not apply water for 2 weeks after Movento or we would not be interested in conducting nematicidal studies in that field. This has been a useful advisory as Movento performance has improved. This strategy has also allowed us to see a bit more clearly how other factors can impact nematicidal properties of Movento. The eventual goal is to fine-tune this recommendation and this year we have made some headway in that direction. The impacts of irrigating too soon, use of an Admire application 7 days ahead of Movento and the impact of Movento on root-knot compared to ring nematodes are presented in the attached power point. This single presentation provides quantification as these three factors are taken into account when Movento becomes available for commercial settings. This data set also leads this author to alter slightly the recommendation of 2 weeks of non irrigation after a Movento treatment. During 2010 our new strategy will be: Irrigate well at least 4 days ahead of the Movento spray and do not irrigate for 9 days after the Movento spray. The main determinant that leads this direction is yield data as shown in the power point. Consider both of these strategies as a work in progress.
Movento can enhance fruit quality and hasten maturity- Does this actually happen? Yes, it has now been observed in a Delano trial for each of the last three years. Where does this physiological change originate. Is it tied to damage caused by nematodes or is it a general phenomenon? Is it always of benefit? Consider assessments of fruit quality when conducting experiments with Movento.
In Summary- Some of the factors influencing efficacy of this new nematicide have been identified. Additional factors will become apparent in the future but as of today growers of perennial crops can achieve a 50% reduction in nematode population levels over a five to six month period after a single Movento application. Five to ten soil samples from a treated row compared to five to ten samples from a nearby untreated row at 100 days after treatment can provide an answer as to the level of population reduction achieved in a given field setting. If at least 30% nematode control was not achieved; consider carefully the prevailing factors during the time of Movento application.