RAMP is USDA's Risk Avoidance and Mitigation Program grant awarded to Glades Crop Care, Inc, U. of Wisconsin (Prof.'s Walt Stevenson and Jeff Wyman) and Benbrook Consulting

In the past season, September 1, 2002 to the present Glades Crop Care has made significant strides in pursuing alternative pest management strategies for the high value vegetable crops grown in Florida as described in our USDA RAMP grant work plan. These activities began last fall with evaluations of growers' bacterial spot control trials and finished with georeferenced mapping of the migration of the very damaging silverleaf whitefly. In between, additional exciting progress was also accomplished.

Our RAMP team, including our cooperating researchers from the University of Wisconsin and Benbrook Consulting Services met in January to review our goals and progress. The interaction was outstanding with significant information and guidance exchanged on key issues.

• Resistance management, especially regarding the strobilurin fungicides, and nicotinoid insecticides. Recent trends with these new pesticide classes prompted the group to make developing a database of resistance management resources one of our key objectives.

• Pest distribution and mapping were reviewed. Insights into the distribution and movement of Colorado potato beetles in Wisconsin potato fields provided valuable ideas on approaches to apply GPS/GIS technology to our pest management challenges in Florida.

• Eco-labeling and IPM measurement were reviewed, especially in light of Wisconsin's first year's experience in the Protected Harvest program. Setting risk reduction goals, an important component in both IPM measurement and Eco-labeling -was discussed at length.

A requirement set by the USDA for all RAMP projects is the establishment of an advisory committee, which met for the first time in early February. This body, a cross section of the agriculture community, includes 1) a representative of the tomato commodity group, 2) growers, 3) a University of Florida Department chairman, and 4) representatives from environmental groups and agricultural policy makers. A high priority concern of the group was the importance of water quantities and qualities in Florida's agriculture and environment.

A second important outcome of this meeting was a thorough discussion of the feasibility of an Eco-label for Florida tomatoes. Our initial conclusion was that, considering the types of commodities involved along with the marketing windows and strategies employed, developing an across-the-board label which would promote all of Florida's high value crops, might be preferable to focusing on one crop at a time.

Many other issues were discussed at these meetings, and we have tried our best to incorporate into our ongoing research the very high level of knowledge and advice we received.

Our research is focused on several critical issues facing our Florida growers. As some of you know our RAMP grant work plan is focused on developing bio-IPM preventive based practices that will mitigate pesticide uses, especially those covered in the FPQA, including Telone.

• Nematode management will become a critical issue for growers in the post methyl bromide era. The most likely substitute for methyl bromide is Telone in any of its formulations, except in Dade County. While Telone is a good nematicide, applications costs are high. Therefore, any strategy that targets Telone to only those acres with a treatable nematode population will 1) be more environmentally acceptable, 2) reduce worker exposure concerns, and 3) save growers money in the long run. We feel that we may be able to do exactly that based on the results of two of our RAMP research projects.
  1. We have found that where tomato fields have not been fumigated for two seasons, root knot nematode populations can be restricted to areas of less than 1 acre. By plotting the nematode distribution from our assay results with a GIS system, a map of infested areas can be produced that will allow the grower to apply Telone only in those areas with a treatable population. Our preliminary data show that control applications could be reduced by one-half to two-thirds.

  2. Root knot nematode (RKN) monitoring can be tedious and may return questionable results. This is because the accuracy of soil sampling for nematodes relies heavily on the season, the presence of acceptable hosts and on soil conditions. With this in mind, we have investigated several sampling methods to determine which will produce the most consistent and useful results. Two types of host plant sampling appear to be more productive than the standard soil sampling techniques. These involve crop sampling, in which the roots of randomly selected plants are examined at the end of the crop. Any RKN produced galls on the roots are assigned a numerical grade, and the average grade for a sampling area is assigned to the corresponding grid on the field map. UF/IFAS nematologists have also successfully tested this method. But what about detecting RKN in unplanted areas? To do this we have developed a bioassay that uses cucumber seedlings planted in soil from the area in question. At the end of 4 weeks the soil is removed from the roots and examined for galling. Because of the extreme sensitivity of cucumber to RKN, this method allows an accurate evaluation of RKN densities-even in fallow fields. Again, the results can be tied back to a gridded GPS field map. The result is that the grower can more effectively and efficiently target his Telone applications.

• Pest movement from field to field and farm to farm is a concern, especially during the critical period when the fall crop is ending and the spring crop is being planted. We took advantage of the high populations of silverleaf whiteflies (SLW) and Tomato Yellow Leaf Curl Virus (TYLCV) incidence that were present this past spring to evaluate the movement of these pests from fall fields to spring fields. To summarize, using GPS mapping technology, we found that SLW probably take advantage of air currents (wind) to move from field to field. We also found that the significant risks of TYLCV disease occur at both short and long distances from an inoculum source. The reliance of SLW on air currents during migration has been well documented around the world. Our research results firmly demonstrate this phenomenon in the Immokalee area, where even the presence of dense woodland and swamps could not effectively block the apparent movement of SLW along with its vectored virus, TYLCV, into spring fields from distances up to 8 miles away. We also looked at leafminer movement into newly planted fields and found that the effects of air currents appear weaker on them. This is likely due to the fact that they are stronger fliers than SLW.

• What happens to pest populations at the end of a crop season? We are trying to answer this question in several ways. At the end of the spring tomato crop, we collected data from wind oriented traps placed around a tomato field during the crop destruction process. Our goal was to confirm the movement of SLW on air currents. The results of the initial test were inconclusive. Periods of extended calm - when the SLW may have flown upwind or because the bulk of the SLW in the trial area probably rode morning thermal air currents to elevations higher than the traps are possible explanations for lack of confirmation. Further wind-oriented trapping may be done in the upcoming season, but trap height including further literature research will have to be evaluated to make this effort more fruitful.

• We have also investigated the efficacy of alternatives to FQPA-targeted pesticides in the management of key vegetable pests. We have found that managing bacterial spot will remain-at least for the near future-heavily reliant on all the field sanitation, cultural controls and other preventive practices available to growers. Observations on the alternatives Oxidate and Actigard indicate that neither can stop an epidemic once underway. Results from our and growers' small plot tests here in Florida and from researchers in other parts of the South indicate that the yield reductions associated with Actigard may be avoided through better application timing, and may also depend on seasonal factors, such as daylength and average temperature. Further testing with alternative bacterial spot control materials and strategies is planned for the upcoming season.

• We have begun cataloging the beneficial insects that occur in south Florida vegetable fields, especially parasitic wasps attacking leafminers. This effort will lay the groundwork for conserving or possibly augmenting these important biological control agents in order to further extend the effective lifetimes of our current leafminer control materials, Trigard, Agrimek and Spintor. If augmenting existing parasite populations becomes desirable or necessary, it will be to our advantage to know what species are able to survive and function effectively in significant numbers in the chemical environment of tomato production fields. Since several species of leafminer parasites are currently available from commercial insectaries, this information should help interested growers make appropriate purchases.

We are proud of the progress we have made under this grant in developing pest management tools for vegetable growers. We are looking to the upcoming season, which we expect to be even more productive. As always, we will need cooperators who can work with us in this research. Especially important will be cooperators who are willing to place parts of their crops into demonstration plots where the results of our research can be put to use. Please let us know if you are interested in helping us in this important effort.