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August 1998 Volume 36 Number 4 |
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Integrated Pest Management
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| 1. ARTHROPODS foliar aphids (melon aphid, cowpea aphid), whiteflies, squash bug, cucumber beetles (various species), leafminers, leafhoppers, spider mites, thrips, rind-worm complex (melonworm, pickleworm, cabbage looper, corn earworm, armyworms), seedcorn maggot, squash vine borer, ants, darkling ground beetles, false chinch bugs, field crickets, grasshoppers, lygus bugs, leafrollers, saltmarsh caterpillar, flea beetles, flea hoppers, japanese beetles, stink bugs, cutworms, wireworms. |
| 2. DISEASES vine declines (monosporascus root rot, charcoal rot, gummy stem blight, fusarium wilt, yellow vine), downy mildew, insect-transmitted viruses (watermelon mosaic virus, papaya ringspot virus, zucchini yellow mosaic virus, cucumber mosaic virus, squash leaf curl virus), bacterial wilt of cucurbits, bacterial fruit blotch, powdery mildew, anthracnose, cercospera leafspot, alternaria leafspot, Phytophthera spp. rot, angular leaf spot, choanephora wet-rot, fusarium rind rot, reniform nematodes, root knot nematodes. |
| 3. WEEDS pigweed (Amaranthus species), various grass species, pie melon, and nutsedges (particularly in plasticulture) and many others (not fully represented). |
| 4. VERTEBRATES various bird and rodent species that feed on seeds and seedlings, as well as birds, coyotes, raccoons and opossums that feed on fruit and deer that feed on foliage. |
The results of the workshop surveys identified and ranked the most important pests in the view of the participants at the workshops. Table 2 represents the combined response of 168 workshop participants in Texas to the question, "What are the three most manageable and the three most unmanageable pest problems in cucurbit crops?". The participants included agricultural producers (small farms to large corporate farms), packers and processors, crop consultants, pesticide industry representatives, federal researchers, state researchers, and Extension specialists. From the 626 individual responses, 28% were only identified to categories, such as insects, fungi, etc., that were too general to make any logical pest management decision. In addition, 3% of the respondents misidentified a pest problem, for example, "rust" or pollination as a pest. This suggested that there is a serious need for better pest identification and training so that at least the pest species and disease agents are properly identified among the IPM team members.
It was expected that there would be some respondents that would not classify the pests as manageable or not, but the resulting 36% unclassified pests was higher than expected. This could reflect an inability or unwillingness to properly categorize pests in terms of their manageability, which suggests that better pest identification/classification training is needed. On the other hand, the responses did clearly point out the pest categories that most occupy the IPM team members attention (Table 2). These were: (a) insects (341 responses, 54%), (b) fungi (129, 21%), (c) weeds (52, 8%), (d) virus (25, 4%), and mammals (23, 4%). Interestingly, government personnel was indicated as a pest in a few responses.
Table 2
Participant-Identified Cucurbit Crop Pests
(most manageable and unmanageable, or unclassified)
Indicated as Number of Responses per Category
Based on 168 Total Respondents in Texas
| Pest Type | Pest Classifications | |||
|---|---|---|---|---|
| Manageable | Unmanagable | Unclassified | Total | |
| Insects (general) | 13 | 16 | 35 | 64 |
| aphids | 18 | 25 | 32 | 75 |
| melon/pickle worms | 30 | 10 | 24 | 64 |
| squash bug | 4 | 13 | 27 | 44 |
| whiteflies | 3 | 16 | 12 | 41 |
| cucumber beetles | 13 | 5 | 16 | 34 |
| stink bug | 1 | 1 | 6 | 8 |
| thrips | 3 | 1 | 2 | 6 |
| leafminer | 0 | 0 | 3 | 3 |
| ants | 0 | 2 | 0 | 2 |
| Fungi on foliage and fruit (general) |
12 |
27 |
15 |
54 |
| downy mildew | 13 | 5 | 4 | 22 |
| anthracnose | 3 | 5 | 5 | 13 |
| melon blight | 0 | 5 | 3 | 8 |
| powdery mildew | 2 | 0 | 5 | 7 |
| gummy stem blight | 1 | 2 | 0 | 3 |
| "rust" or ID error | 0 | 0 | 3 | 3 |
| Fungi in soil (general) |
0 |
2 |
0 |
2 |
| vine declines | 0 | 23 | 6 | 29 |
| Fusarium | 2 | 6 | 0 | 8 |
| Weeds (general) | 10 | 4 | 4 | 18 |
| grasses, sedges | 26 | 4 | 4 | 34 |
| Viruses (general) | 4 | 18 | 3 | 25 |
| Mammals: birds, rodents, etc. |
10 |
10 |
3 |
23 |
| Bacterial wilt | 1 | 10 | 3 | 14 |
| Mites (general) | 3 | 1 | 4 | 8 |
| Other miscellaneous | 4 | 3 | 1 | 8 |
| Nematodes (general) | 0 | 2 | 2 | 4 |
To further describe the current status of IPM in terms of implementation, the following question was asked in the workshop survey (Table 3). "What are IPM practices (give one example) and do you think that the use of this practice improves the image that U.S. Consumers have of the agricultural industry?" This double topic question was formulated to determine if the participants had a good grasp of the working of IPM and at the same time test their acceptance of these practices. Of the 168 respondents, 163 (97%) answered the first part of the question and only 71 (42%) answered the second part. One third of the responses to the first part had to do with the use of scouting and thresholds. Biological control, reduced pesticides, and cultural controls were also seen as important practices.
Table 3
Top Eight Examples of IPM Practices Given by Texas
Workshop Participants Ranked by Total Responses
| Practices | Total |
|---|---|
| Use of scouting and thresholds | 53 |
| Enhancement/release of beneficials | 39 |
| Reduced pesticide applications | 25 |
| Crop rotation/plowing residues | 19 |
| Bioengineered (Bt) plants | 4 |
| Information | 4 |
| Adjusting planting date | 3 |
| Host plant resistance | 2 |
Other examples not listed in Table 2 were weed control, use of organic pesticides, spraying field perimeters, economic and environmental health, weed and bug control, reduce seed borne disease, airplane spraying, improved crop quality, and monitoring weather. In general, the results indicated that the participants had a reasonably good grasp of the what IPM involved. Of the 71 responses for the second part, 58 (82%) stated that IPM improved the image of the agricultural industry and 13 (18%) did not, but the overall lack of response to this question (only 44%) indicated that there was either an unwillingness to form an opinion or a lack of knowledge as to how IPM is viewed by the U.S. Consumers. Also, two respondents specifically stated that there was a lack of publicity about what IPM is and its benefits to the U.S. Consumers.
To determine if IPM was being used and whether or not its use was perceived as a risky proposition, the following question was asked. "Do you use or endorse IPM and do you think it increases or decreases production risks?" Surprisingly, 132 (89%) of the 148 respondents already used or endorsed the use of IPM, only 13 (9%) did not, while 3 (2%) were uncertain. Even though this was encouraging for IPM proponents the second part of the question revealed an important problem related to this enthusiastic response, i.e., perceived increase production risk to 37% of the respondents. Fifty-five (56%) of the 98 respondents to the second part of the question felt that IPM reduced production risks, but as long as this percentage does not rise, attaining the USDA targeted 75% use of IPM in cucurbit crops in the year 2000 is unlikely given that a majority of vegetable producers are risk aversive.
To evaluate constraints to the implementation of IPM the following question was asked (Table 4). "What are the biggest constraints on IPM?" The majority of the participants clearly indicated that information, and the integration of that information, was lacking for various pest problems. Also, specific IPM practices needed to be tailored to specific agricultural production locations.
Table 4
Top Eight Examples of Constraints to IPM Given
by Texas Workshop Participants Ranked by Total Responses
| Constraints | Total |
|---|---|
| Lack of information and integration | 44 |
| Time/dependable personnel for management | 30 |
| Problems hitting market/production windows | 26 |
| Environmental/weather | 17 |
| Economics/lack of money/cost of scouting | 8 |
| Lack of adequate thresholds | 6 |
| Lack of experience with IPM | 5 |
| Producer's resistance to change/fear of losing control | 5 |
Constraints not listed in Table 3 were production risks (based on zero tolerance of pests), lack of available tools and chemical labeling, lack of qualified applicators and scouts, researcher's pesticide-oriented mentality, slow response to crisis situations, neighbors killing beneficial organisms, IPM is too much work and too crop specific (too much information), time lapse in control, staying on top of problems, organic production, synchronizing beneficial/damaging pest life cycles, soil management, and consultants protecting themselves. The importance of specific commodity markets and time constraints was evident in these responses.
The final question in the workshop survey was, "What is the most important thing that agencies (Experiment Station, Extension Service, Department of Agriculture) can do to improve pest management in cucurbits (Table 5)?" Again, the importance of IPM Extension, IPM research, and formal educational programs were highlighted by the responses. Also, there appeared to be a need for pest forecasting as well as providing current IPM information.
Table 5
Top Eight Examples of Agency Activities Suggested
by Texas Workshop Participants Ranked by Total Responses
| Activities | Total |
|---|---|
| Provide information through technology transfer (extension, on-farm trials, printed information, etc.) |
72 |
| IPM research trials | 42 |
| Education and Conferences | 13 |
| Provide information on current pest situations/forecasts | 7 |
| Increase involvement in IR-4/product registration | 6 |
| Conduct more pesticide trials | 6 |
| Provide better thresholds | 5 |
| Rapid and accurate pest and disease diagnosis | 3 |
The IR-4 program and product testing continued to be important as expected for a vegetable crop, since pesticide labeling (because of regulatory issues) and pesticide efficacy (because of pest resistance to chemical pesticides) are such dynamic issues. Other examples not listed in Table 4 were research on pathogens and their control, government inspection of commercial fields to check for problems, improved marketing, economic data on IPM, providing more money for agriculture, more tests on actual problems, increased industry support, increased yield quality and profit, development of spray schedules, agricultural weather forecasting, promotion of the use of natural insect enemies, work on the nutsedge problem, be involved with pest control, control all government expenditures, develop resistant varieties, and finally to let growers be aware of the agencies.
Table 6
Top Examples of Constraints to IPM Identified by
Hydro, Tulsa, and Rush Springs, OK Workshop
Participants, Respectively (total votes in right column)
| Constraints identified at Hydro | Total |
|---|---|
| Government regulations on pesticides constrain IPM | 28 |
| Government regulations interfere with IPM practices | 27 |
| Lack of information on economics of new IPM practices | 20 |
| Regulations are too tough for registering new pesticides | 20 |
| Constraints identified at Tulsa | Total |
| Lack of validation for products, methods, and equipment. | 15 |
| Lack of knowledge of IPM tools. | 11 |
| Lack of crop protection and production workshops. | 10 |
| 'Can't teach old dogs new tricks'. | 10 |
| Constraints identified at Rush Springs | Total |
| Too many EPA regulations | 9 |
| Loss of pesticide registrations | 5 |
| Economics | 4 |
| Lack of better pesticides - more effective | 4 |
The Oklahoma surveys were based on counts of votes and the top priorities were determined and ranked. In response to question #1, all growers with one exception indicated by show of hand that they believe that they use IPM on their farms. In a second workshop at Hydro at an annual vegetable grower meeting in February 1996, the priorities for research and extension were further examined with a similar facilitated survey. Again, all but one participant stated that they currently used IPM on their farms. Finally, at a workshop/grower meeting at Rush Springs all the respondents (13 growers) stated that they currently used IPM on their farms. The responses to questions #2 and #3 for all three workshops are listed in Tables 6 and 7, respectively.
Table 7
Top Examples of Priority Research and Education Needs
for IPM Implementation Programs Identified by Hydro, Tulsa,
and Rush Springs, OK Workshop Participants,
Respectively (total votes noted in right column)
| Priority needs for research and education at Hydro | Total |
|---|---|
| Pesticide trials/evaluations | 55 |
| Establish more and better pest thresholds | 29 |
| Research/education on beneficial insects and pollinators | 25 |
| Priority needs for research and education at Tulsa | Total |
| Crop coefficients for irrigation needs. | 13 |
| Technology demonstrations. | 12 |
| Pest control (insects and disease). | 11 |
| Weed control. | 9 |
| Weather-driven plant and pest models (MESONET). | 9 |
| Third party registrations of pesticides. | 8 |
| Minor-use pesticide development and registration programs. | 6 |
| Priority needs for research and education at Rush Springs |
Total |
| Economic thresholds for insects | 7 |
| Careless (pigweed) weed control | 7 |
| Aphid and squash bug control/management | 6 |
Grower priority needs from Oklahoma-based producers were combined with those from Texas (producers, representatives of various agricultural industries, and government agencies) and a short list of priority needs were developed based on these responses. From Oklahoma and Texas the following were determined to be the top priorities for research and extension programs in the region:
First, agencies need to improve IPM delivery systems and technology demonstrations to get clear, user-friendly instruction to growers, agricultural consultants, and other users of IPM technology.
Secondly, more research is needed on specific problems, such as weed management, arthropod vectored virus control, soil borne pathogen management, foliar and fruit insect management, foliar and fruit pathogen management, beneficial insects (pest predators, pest parasites, and crop pollinators), etc., with priority ranking strongly differing between locations in Texas and Oklahoma.
Thirdly, more workshops and other formal educational conferences are desired for specific vegetables crops. They are seen as useful and concise mechanisms for providing information on IPM, particularly when printed materials on crop specific IPM were provided in the workshops. Crop-specific IPM books with color plates were highly desirable teaching materials at all of the workshops (e.g., "Cucurbit Production and Pest Management," OSU Circular E-853).
Fourthly, crop production issues, such as cultural practices, marketing windows, crop coefficients for irrigation, etc., need to be more integrated with pest management in any IPM programs that are developed for the producers for them to have any chance of adoption. This was one of the concerns that we attempted to address in the workshops by providing a comprehensive educational program along with the opportunity for questions and facilitated discussions.
Finally, assessment of IPM programs by representative IPM Team members, their economic viability, and annual re-evaluation for progress toward specified goals was seen as very important. The priorities identified in the workshop surveys attest to the importance of getting "outside" input.
Discussion
The information presented in the workshops indicated that there is an abundance of IPM knowledge available, although certain serious pest problems continue to need research to find solutions. From the survey it appeared that IPM was fairly well understood by the workshop participants and was generally accepted as useful. The main tools for management of the pests included application of pesticides, disease resistance incorporated into cultivars, and cultural practices such as planting dates, field rotation and soil cultivation. Thus, it is likely that some integration of control tactics is already being used.
Disease resistance incorporated into cultivars was viewed as desirable, but is dependent upon commercial seed company interest and is driven by the economics of scale; for example, sufficient acreage and seed sales to warrant research and breeding. Use of planting dates and rotation is driven by economics; for example, market windows based on harvest dates and availability of suitable crop land with irrigation. The use of pesticides (a primary tool) is dependent upon availability of effective materials, regulations affecting the use of the materials on specific crops in specific regions and to a lesser extent on the impact on non-target organisms (i.e. honeybee pollinators), and human and environmental concerns (mammalian toxicity and handling, danger to aquatic organisms).
An effective integrated strategy for pest management is therefore affected by economics of production, government regulations, effective management strategies and education programs that transfer current research results to the industry. Considerable research has been conducted to develop IPM practices over the past decades either through the agricultural experiment station system, USDA/ARS and/or private agricultural industry. Production and pest management methods resulting from this work have been transferred into practice with varying degrees of success.
Based on informal discussions at the workshops, it was apparent that current pest management still relies heavily on chemical pesticide controls. However, workshop participants understood that there are limitations to this tactic including: (a) development of resistance to chemicals (for example, systemic fungicides like metalaxyl, benomyl, thiophonate-methyl, fosetyl Al, tridimefon); (b) the high costs associated with treatments in terms of both the application costs and environmental effects; (c) no clearly defined use recommendation based on economic thresholds; (d) lack of specifically needed products, such as fungicidal seed-treatments (no systemic fungicides currently labeled for seed treatment); (e) lack of advisories (forecasting systems:) for most foliar diseases; (f) lack of implementation of developed advisories; and (g) lack of systemic fungicides with eradicating properties (post-infection activity). Based on these discussions it was also apparent that other pest control tactics that need further evaluation and study included cultural controls, host plant resistance, and biological controls (antagonists, etc.).
There is a perceived lack of effective commercially- available biological control agents for management of pathogens. One participant commented that biological control of post-harvest diseases may be achieved using controlled environments. Field evaluations were viewed as necessary to determine the effectiveness of these same biocontrol agents in field conditions. Many participants felt that there is a lack of development of cross-protection to plant viruses in host plant resistance work. Systematic seed certification and seed health testing were also viewed as important in this area.
Regulatory control is another tactic that has been under utilized in pest management programs. This includes testing for seed and transplant health using certification/inspection methods. In the future the results of these surveys should be used to develop priorities for research and extension programs in the south-central region of the USA.
This article is online at http://www.joe.org/joe/1998august/a3.html.
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