Pest Management Infrastructure

Transcription

1 Pest Management Infrastructure Beth Grafton-Cardwell UC/Lindcove Research and Extension Center, Exeter UC/Kearney Ag Center, Parlier Entomology, UC/Riverside This Citrus Research Board funding supports three Staff Research Associates (SRA) located at the Kearney Agricultural Center and Lindcove Research and Extension Center. These SRAs direct an additional four laboratory Assistants whose salaries are funded by other grant sources. Projects supported by this CRB funding include: Insect Rearing Programs: At the Kearney Ag Center, we rear California red scale on banana squash, citrus leafminer on citrus seedlings, and citrus peelminer on zucchini squash as the foundation for a number of research projects. The California red scale colonies are used as standards for testing field populations for pesticide resistance. The citrus peelminer colony provides moths for pheromone research by Jocelyn Millarís group (UCR Entomology), eggs and larvae for insecticide screening work, and larvae for Bob Luckís program (UCR Entomology) to screen new parasites for their acceptance of citrus peelminer. The citrus leafminer colony is used for pesticide screening work and other experiments as they arise. Pesticide resistance monitoring in California red scale: During July-October of each year, pest control advisors submit samples of California red scale-infested green fruit. We have the ability to test for organophosphate (Lorsban and Supracide) and carbamate (Sevin) resistance using an esterase enzyme biochemical test. Organophosphate resistance continues to be common due to continued use of organophosphates for citricola scale. We found that 48% of 68 California red scale populations tested during had high levels of resistance to organophosphate insecticides. Thus, organophosphate and carbamate insecticides are not useful for California red scale control in many situations. We also test for Esteem resistance by dipping scale-infested green fruit in a discriminating concentration (10 ppm) of Esteem and waiting 2 weeks to see if the scales successfully molt. Esteem resistance (> 10% survival of 10 ppm) was detected in 10% of the 60 populations tested in the laboratory during We are not sure if this level of resistance translates to field failure, but it suggests that California red scale populations are starting to develop resistance to Esteem. Growers should avoid continuously using Esteem for California red scale control as that practice will accelerate the rate of resistance. Pesticide resistance monitoring in citricola scale: We have developed a citricola scale bioassay that al- lows us to test for Lorsban resistance in citricola scale. The method consists of dipping citricola scale-infested leaves in Lorsban, ringing the leaves with stickem and placing them on moist cotton for 5 days to determine mortality. Scale from a susceptible organic and a resistant conventional orchard were bioassayed multiple times using a series of concentrations of Lorsban to define a concentration (178 ppm Lorsban) that would distinguish between susceptible and resistant populations. Bioassays of citricola scale from 39 San Joaquin Valley orchards during indicate that about 29% of the orchards have scales with significant levels of Lorsban resistance. Resistance results in shortened residual efficacy of Lorsban: where it once suppressed citricola scale for 3-5 years, now it only suppresses populations for one year. Growers in orchards with resistant citricola scale will need to use different insecticides for citricola scale control, such as Admire, Assail or Applaud.

2 Web-based data management: Citrus Entomology web pages ( We produce numerous web pages that provide degree day unit information on California red scale and citrus peelminer, lists of recently registered pesticides, and lots of basic information about citrus pests for pest control advisors (PCAs). This information helps the PCAs more effectively manage pests. ArcIMS web-based pest reporting: Working with Kris Lynn-Patterson and her Geographical Information Systems (GIS) staff at the Kearney Ag Center, we have created a web site where PCAs and growers can enter pheromone trap counts for citrus leafminer or peelminer. Kris Lynn-Patterson provides the data back to our laboratory as maps and this helps us keep track of where the pest problems are. This technology is useful for any pest that growers are willing to provide us information for, especially new pests that are entering the area. Mapping LREC: We are currently developing an ArcGIS map of the Lindcove Research and Extension Center. The first phase of the mapping is to identify the geographical location of every tree and its rootstock, scion, and year of planting. The next phase will be to associate every activity that occurs to the tree (routine pesticides, irrigation, pruning, harvest dates) and every piece of data collected (yield, grade, fruit quality, CTV testing, experimental pesticides, and pest counts). These data would be not be available to the general public, but used in-house by researchers and Center staff. Summary data could be provided to the Citrus Research Board committees as needed. Figure 1. The citrus leafminer moth. (Photo credit: Jack Clark, UC/ANR Communications) Citrus Peelminer and Citrus Leafminer Monitoring: We are working with various researchers to improve management of citrus peelminer and citrus leafminer in the San Joaquin Valley. Citrus Peelminer: We monitor citrus peelminer in the San Joaquin Valley using pheromone traps checked weekly from March through November. We evaluate susceptible varieties of citrus in the fall and estimate the percentage of damaged fruit from 1,000 fruit samples. Dave Headrickís group (Cal Poly/San Luis Obispo) determined that citrus peelminer attacks stems of walnuts and other plants during the first two generations in the spring starting in early March. The third and fourth flights of citrus peelminer deposit eggs on pummelos and grapefruit during June and July. The fourth through seventh flights of peelminer deposit eggs on oranges during August through October. Pesticides have been only partially effective in controlling citrus peelminer, even though in the laboratory many insecticides are toxic to the eggs and larvae (Baythroid, Danitol, Lorsban, Success, Agri-Mek, Assail). This suggests that coverage of fruit low and inside the tree is the limiting factor for insecticide efficacy. Natural enemies are not very effective in the San Joaquin Valley. Robert Luck ís group is rearing and providing Cirrospilus parasites from the Coachella Valley for us to release in San Joaquin Valley citrus. We are hoping that this parasite will establish and provide more control than the other parasites found in this region.

3 Citrus leafminer: Leafminer has only recently arrived in the San Joaquin Valley. It does not affect yield of trees over 4 years of age in this region, and so we are recommending that growers ignore the damage. Young trees will require annual treatments of Admire, and nurseries will require frequent pesticide treatments. We have placed pheromone traps throughout the San Joaquin Valley and find that populations are heaviest in October and November. Since citrus peelminer and leafminer share many of the same parasites, it is hoped that as leafminer establishes, biological control of both species will improve, reducing the need for insecticide treatments. Robert Luckís group is studying the potential of an imported species of parasite (Citrostichus) to control both pests. Pesticide Trials: We conduct 5-10 pesticide trials at the Lindcove Research and Extension Center and in commercial citrus orchards each year. During 2007, these trials include testing various rates, timing, and combinations of oils and surfactants for the following pests. Citrus red mite: A number of new miticides have been recently registered (Fujimite, Zeal, Envidor, Zoro, and Kanemite) or are soon to receive registration on California citrus. Our studies indicate that all of these miticides are effective against citrus red mite. Most of the miticides are found in different chemical classes and rotation from one class to another will help to prevent resistance from developing in the field and the nurseries. Figure 2. The bioassay method for testing for Lorsban resistance in citricola scale. Citricola scale: Citricola scale is a major pest of San Joaquin Valley citrus, and we continue to search for new effective insecticides to improve control. We are actively screening new, unregistered insecticides, including Movento, Actara, and Platinum to try to find replacements for Lorsban as resistance to that product in citricola scale is increasing. We know that Applaud and Assail have efficacy against citricola scale, and we have established a long-term field trial to compare the level and residuality of their activity. We are also studying a new formulation of Lorsban that should help reduce the volatile organic compound (VOC) impact of Lorsban on the ozone. California red scale: We are studying various adjuvants, water volumes and timings of a new product, Movento, that is a foliar systemic insecticide. If it works well against California red scale, the systemic aspect of the insecticide will allow growers to reduce water volume and greatly reduce application costs. It seems to have efficacy against other pests such as citrus thrips and citrus red mite. It is also very soft on natural enemies including Aphytis and vedalia beetles.

4 Citrus peelminer: We continue to search for a more effective insecticide for citrus peelminer control. The Micromite or Dimilin insect growth regulator reduces peelminer egg hatch. We are experimenting with combining this pesticide with insecticides that have adulticide qualities to see if we can improve control. Generally, insecticides only provide about a 50% reduction in peelminer damage. This is because the fruit that citrus peelminer attacks is low and inside the tree where it is difficult to reach with sprayers. Ants: We have several insecticide trials studying the effectiveness of Vitis liquid ant bait (imidacloprid) against native southern fire ant in the San Joaquin Valley and native gray ants in lemons in Ventura. Vitis acts to reduce ant populations, however, we expect that it may take several years to have a significant impact on ant densities. NOTICE: The research results included in this publication are summary reports for the benefit of the Citrus Research Board and the growers it serves. They are not to be taken as recommendations from either the individual reporting or the agency doing the research. Some of the materials and methods mentioned are neither cleared nor registered for commercial use. The summaries were written by the project leaders identified. Both technical names and registered trademarks of materials are used at the discretion of the authors and do not constitute any endorsement or approval of the materials discussed. Questions on possible applications should be directed to the local University of California Extension Specialist, a licensed PCA, or the appropriate regulatory agency.

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