Project No.:              Non-Funded Research        

Project Leader:       Frank Zalom

Cooperating Personnel: S. Brodt, R. Krebill-Prather, W. Bentley and C. Pickel (UC Statewide IPM Project), K. Klonsky (Agricultural and Resource Economics, UC Davis), J. Connell (UCCE, Butte Co.), L. Wilhoit (CA Dept. of Pesticide Regulation), M. Gibbs (CAFF)

Objectives

1.  In association with PMA partners, conduct a mail survey of California almond growers to determine growers’ perceptions of pest priorities, pest management practices used, attitudes towards IPM, interactions with PCAs, information sources used and other information.

2.  Summarize responses and conduct appropriate cross-analysis of survey questions.

3.  Compare responses from the 2000 survey with comparable questions asked in a 1986 survey on almond growers' pest management practices.

4.  Prepare results for publication in the PMA newsletter, California Agriculture, and the UCIPM website.

Frank Zalom, UC Davis, discusses results of the IPM survey at the Almond Board conference, Dec. 1, 2004.

Summary of Results

Increasing adoption of Integrated Pest Management (IPM) practices to improve pest control and reduce growers’ need for broad spectrum pesticides has long been a goal of the University of California Statewide Integrated Pest Management Program (UCIPM).  With almond production distributed on more than 6,000 farms and acreage approaching 540,000 statewide, almond growers and their pest control advisers (PCAs) are not surprisingly a major focus for University of California (UC) research and extension efforts.  The almond industry has worked closely with UC for over 35 years to develop and implement new IPM practices, and the implementation of these practices in the almond industry has led to its recognition by the US EPA, the California Department of Pesticide Regulation and other agencies and organizations as leaders among agricultural commodities.

California almond growers were chosen by the USDA in 1985-86 as one of 10 state 'case studies' for a national evaluation of Extension IPM Programs intended to identify IPM practices promoted by Cooperative Extension being used in the states, and to document impacts of the use of these practices.  UC Davis Agricultural Economist Dr. Karen Klonsky and UC Davis IPM Specialist and Entomologist Dr. Frank Zalom cooperated with the Almond Board to survey almond growers statewide to identify among other things their perceived pest problems, use of various pest management practices, knowledge of IPM and sources of information.  Results showed that a majority of growers used the 4 point program for navel orangeworm, dormant sprays for peach twig borer and San Jose scale, and other practices.  IPM use had significantly reduced meat damage by navel orangeworm and peach twig borer, as well as total use (especially in season use) of organophosphate insecticides.

In 1999, as part of a collaborative effort among the partners in the Pest Management Alliance (PMA), a telephone survey of almond growers in 10 counties was conducted to determine the extent of dormant organophosphate and pyrethroid insecticide use in the late 1990s.  The survey was conducted by UCIPM Evaluation Specialist Dr. Rose Krebill-Prather  The purpose was to document use patterns, link use patterns with other farm practices for program evaluation purposes, and provide a baseline by which to measure future change.  Ten California counties with the highest proportion of the almond acreage in the state were selected for the study.  Because the Almond PMA partners’ main focus was on growers for whom almonds were more than a part-time interest, the sampling strategy used was based on number of almond acres grown in 1998.  In each of the regions, a simple random sample of approximately 200 almond growers with more than 20 acres of almonds was selected from the county lists.  Because the study did not want to exclude the substantial number of growers with a small number of almond acres, a fourth group was defined as growers with 20 acres or less of almonds.

Telephone interviewing was contracted out to an independent telephone survey lab, Marketing Works, in Bakersfield.  The UC Statewide IPM Project provided Marketing Works with the finalized telephone questionnaire and supporting survey materials.  Trained telephone interviewers began calling on June 14, 1999, using paper and pencil questionnaires.  Calling continued through the end of July, 1999.  The beginning sample size was 844 farm operations that grew almonds in 1998.  Of these, 155 cases were determined to be ineligible to participate in the survey (no almonds grown, no longer farming, duplicate farm reported, retired, deceased) and 91 respondents refused to participate.  A total of 486 telephone interviews were completed.  The overall response rate is 57.5% and the completion rate is 70.5%.  Only 10% of respondents refused to participate. Among responses of general interest are the insects monitored by PCAs in relation to the PCA's relationship to almond production (Table 1).  These data indicate that most insect monitoring takes place for peach twig borer, navel orangeworm and San Jose scale.  There was no significant difference in monitoring related to the affiliation of the PCA, although in every case more independent PCAs were reported to practice monitoring of each insect species than was the case for agricultural supply company-affiliated PCAs.  Table 2 presents percentage use of some if the most important controls used for control of NOW by California growers in different growing regions.  A large percentage of growers continue to utilize the elements of the 4 point navel orangeworm control program which was first inroduced in the early 1980s.  The most common NOW control practices include winter mummy removal (orchard sanitation) with over 70% of growers practicing this approach, closely followed by early harvest with about 60% of growers practicing this approach. 

Table 1.  Insects monitored by PCA type.

Table  2.  Navel orangeworm management practices by region.

In association with the phone survey, Krebill-Prather and Zalom conducted an extensive mail survey of California almond growers in 2000 to determine growers perceptions of pest priorities, pest management practices used, attitudes towards IPM, interactions with PCAs, information sources used and other information.  The pest management practices were further divided into those which could be classified as monitoring, chemical controls and chemical and biological controls.  Survey questions were developed by a group of individuals representing the PMA partners.  Dr. Sonja Brodt, who replaced Krebill-Prather as UCIPM Evaluation Specialist, analyzed data associated with this survey.  The mail survey was sent to growers in the 10 largest almond producing counties.  450 growers completed survey out of 1151 potential respondents (39% completion rate).  Results describe in detail the interactions of almond growers with their PCAs, and permit comparison with questions asked in the 1985 survey. 

Figure 1 presents almond growers’ perceptions of arthropod problems that required control to prevent economic damage in their orchards in the 1985 and 2000 mail surveys. Navel orangeworm, target of both May and hull split sprays, and peach twig borer, a target of all three spray timings, were important pests identified by both surveys.  The pest status of mites and ants increased in the 2000 survey.  Not surprisingly, there are differences in growers perception of pest status by region (Table 3).

Figure 1.  Grower perception of insects and mites as problems requiring management in their orchards in 1985 and 2000.

Among the findings was that almond growers sprayed insecticides less frequently at all typical spray timings in 1998-99 than in 1985-86 (Figure 2).  Sixty-six percent of responding growers reported spraying insecticides during the 1998-99 dormant season, 22% applied a May spray, and 59% applied a hull-split spray.  In 1985, 93% of respondents reported using dormant sprays, 78% reported using May sprays, and 82% reported using hull-split sprays.  Approximately half of growers responding in both years considered peach twig borer to be a problem that required control to prevent economic damage in their orchards,.  San Jose scale, another target of dormant sprays, was considered a problem by 21 percent of growers in the 2000 survey.

Table 3. Grower perception of insects and mites as a problem by region in 2000 survey.

An article has been submitted to the journal California Agriculture detailing a portion of the survey which deals with grower interactions with their pest control advisers.  Among results detailed in the article are that growers rely substantially on PCAs for pest management decision-making.  Independent PCAs communicate more frequently with growers than do PCAs who are employed by agricultural input suppliers.  Growers who use independent PCAs tend to feel more knowledgeable about IPM, and report the use of more complex pest monitoring techniques and control practices.  Use of insecticide sprays, however, is independent of type of PCA, and has declined substantially since a 1985 survey  in terms of percentage of growers using them.

A number of growers are utilizing reduced-risk approaches for San Jose scale or peach twig borer management as an alternative to the traditional dormant insecticide and oil spray.  Figure 3 gives examples of some of these practices.  For example, one-third of growers reported applying oil alone during the dormant season, a practice shown by UC Cooperative Extension to provide acceptable control of light to moderate populations of San Jose scale.  Almost 40% of growers indicated use of the microbial pesticides of Bt or spinosad for peach twig borer control on some of their acreage.  Pheromone mating disruption for peach twig borer was also reported as used by some growers.

Figure 2.  Percent of surveyed growers applying insecticides in 1985 and 1999 (1985 sample includes all farm sizes; 1999 sample includes only farm sizes > 20 acres).

Ants were mentioned as an increasing problem to growers in the 2000 survey.  Some of the practices used for monitoring and control of ants at the time of the survey are presented on Table 4.  These data will provide a good baseline for future surveys of what growers are doing to manage ants in their orchards, and they also validate that counting ant hills to determine need to apply a control measure was being used by almost a third of growers at that time, while baited traps were being used by another 11 percent of growers.

Although the data set has yet to be fully analyzed, some interesting observations of uses of pest management practices for weeds and diseases were also obtained from the 2000 survey.  These are presented on Tables 5 and 6.

Figure 3.  Percent of surveyed growers applying reduced-risk insecticides for peach twig borer control in 1999.

In summary, grower surveys of pest management practices provide useful information on growers' perceptions of pest priorities, the pest management practices they use, their attitudes towards IPM, and their interactions with PCAs, among other information.  Surveys conducted by the UCIPM Program in association with UC Cooperative Extension, the Almond Board of California and others have provided indications of how growers perceptions of pest problems as well as how their approach to managing pests has changed through time.  This is especially interesting at a time when there is concern for what pest management practices growers are using.  The 2000 survey shows that almond growers, in particular have reduced the number of annual insecticide applications they make over the past 20 years, and that they are also beginning to adopt some available reduced-risk approaches.  The 2000 survey can also become a baseline for future surveys giving almond growers an opportunity to measure how the industry has changed in terms of pest management.

Table 4.  Percent of growers using various monitoring and control practices in the 2000 survey.

Table 5.  Percent of growers using various weed management practices in the 2000 survey.

* significantly different use by region

Table 6.  Percent of growers using various disease management practices in the 2000 survey.