Northeast Region IPM Grants
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| States: | New York, Pennsylvania |
| Project Directors: | Martha Mutschler, Thomas A. Zitter, Charles Bornt, Majid R. Foolad, Alan A. MacNab |
| Institutions: | Cornell University, Penn State University |
| Project Type: | Research and Extension |
| Award*: | $ 122,364 |
| Term: | 36 months |
| Setting: |
tomato |
*Award shown is total amount to be used over the course of the project term.
Dramatic losses in tomato yields and quality during the past several years have been recorded in the Northeast US. Late blight (LB), caused by Phytophthora infestans, and early blight (EB), caused by Alternaria solani and A. tomatophila, are the two most prevalent diseases responsible for these losses. Currently growers must rely upon the extensive use of fungicides to control both diseases. Unless these fungicides are used preventatively, satisfactory control is not obtained. New and more aggressive LB strains have displaced the previous indigenous strains, and these new strains are more difficult to control with fungicide sprays. Repeated use of protectant fungicides and newly introduced strobilurins has lead to loss of effectiveness in the case of protectants, and fungicide resistance in the case of strobilurins, and has made EB control more difficult. Clearly, new alternatives for LB and EB control are long overdue, and we must move forward with new IPM practices in the NE. The goal of this project is to provide immediate relief to Northeastern tomato growers by testing advanced tomato lines developed at Cornell and Penn State with multiple genetic resistance for all known races of late blight and phenotypes of early blight in the NE. This joint research and extension proposal ($110,364 PL89-106 vs. $17,000 Smith-Lever) will deploy the resistance into conventional and organic production systems. The objectives of this 3-year project are to characterize tomato selections for disease resistance, plant maturity, yield and other desirable horticultural characteristics, while testing them at multi-sites and in two states.
The recent creation of tomato inbred lines at Cornell University and Penn State University possessing LB resistance and/or EB resistance created the opportunity to restructure integrated strategies for the control of these important diseases.
Objective 1.
Identify appropriate LB and EB resistant lines for use in regional trials and
possible release.
a) The Cornell breeding program has recently created 32 LB and EB resistant breeding lines, which is more than we could include in regional trials. In yr.1 we will select from these fresh market lines for optimal horticultural characteristics for the NE. All of the available lines will be tested for maturity and key horticultural characteristics to allow selection of the best subset of the lines for inclusion in regional testing in yrs. 2 and 3.
b) The NY breeding program has an additional 17 processing tomato lines fixed for LB resistance, and selected for EB resistance, but not yet tested to determine whether the EB resistance is fixed. Since this group includes lines with some of the earliest maturities and very good fruit quality, it is highly desirable to perform EB screening on this material in yr. 1 to allow inclusion of some of these lines in the regional trials in yrs. 2 and 3. Some of these materials are already ideal candidates for use in organic systems.
c) The PSU tomato breeding program has been developing fresh market as well as processing lines with improved EB resistance. All lines have also been selected for early maturity (suitable for NE production), improved fruit quality (in particular high lycopene content), and adaptation to PA conditions. These lines are particularly high yielding under PA conditions, compared with lines developed elsewhere. The collection includes too many lines (~500) to be considered for inclusion in regional trials. This material will be evaluated in yr. 1 to identify a subset for regional evaluations in yrs. 2 and 3.
d) The PSU tomato breeding program has also identified new sources of LB resistance within L. pimpinellifolium and has developed recombinant inbred lines with strong LB resistance. Currently, introgression of these new sources of LB resistance into fresh market and processing tomato genotypes are underway. In the yrs. 2 and 3 of this project we might be able to include some genotypes in regional trials.
Objective 2.
Test EB and LB resistant lines in regional trials to determine their performance
and utility in traditional and organic systems.
Regional trials will be run in both NY and PA to determine the utility of the
resistant breeding lines developed at CU and PSU. This work will determine which
of these lines best fit the needs of NE tomato production, the levels of control
provided by these lines, and how best to deploy these lines. To be performed
in several counties, with traditional and organic methods, and without the use
of fungicides.
Objective 3.
Release materials and information to enable NE growers to use the new strategy.
The information generated by this work will be provided to extension personnel
and growers through a variety of channels including publication or articles,
and the web site http://vegetablemdonline.ppath.cornell.edu/Home.htm, presentations
at demonstration days held at the research plots, and at stakeholder meetings
in both states. The tomato lines will be released through appropriate channels
to promote their use.
Tomato as a crop. Tomatoes are an important part of a diverse and balanced diet. One medium fresh tomato (135g) provides 47% RDA of Vitamin C, 22% RDA Vitamin A and 25 calories (135g). Tomatoes are rich in the anti-oxidant lycopene, a compound that protects cells from oxidants that have been linked to cancer. Tomato ranks number one in contribution to diet in the United States because of the large quantities consumed.
Tomato is also an important vegetable crop in NE states, including NY, NJ and PA. The acreage in PA, NJ, and NY was 11,000 A with a value in excess of $68 million during 2002 (USDA Statistics, 2002). In PA, tomato is the second most important vegetable crop, with annual farm value of ~$26 million, where it is grown both for both processing (~$6 million value) and fresh-market (~$20 million value) uses. PA ranks #5 in the nation in total production of fresh market tomatoes, and #8 in total production of processing tomatoes (USDA Statistics, 2002). While large-scale production of tomatoes is no longer common in NY, tomatoes are produced by most of the diversified fresh-market vegetable producers, and the total value is in excess of $24 million.
The immediate problem. LB is a foliar/fruit disease that occurs throughout tomato growing regions of North America with varying frequency, depending on whether weather conditions are favorable. The magnitude of the problem of controlling LB is reflected in it being identified by grower groups throughout the country as a major pathogen. In NY LB occurs yearly, but the intensity of the disease and the races of the pathogen found can vary with year and conditions. In PA, LB does not occur as often as EB; however, when LB occurs it is much more devastating than EB. In 2004, LB was confirmed in at least 26 PA counties. Some commercial organic planting and many home garden plantings of tomato in PA were destroyed by the sudden occurrence of LB in the eastern and south central part of the state. Significant losses also occurred in some commercial plantings when fungicides could not be applied at some critical times due to extended rainy periods. In addition, growers who applied fungicides as needed to save the crop in 2004, ended up applying many more fungicides than usual to attain this control. Up to 20 sprays were needed in some areas as compared to an average of about eight sprays. The same scenario was also played out in parts of NY (9 counties) and NJ (3 counties) during the 2003 and 2004 seasons, EB, caused by Alternaria solani and A. tomatophila, is annual problem and is the most common foliar disease in the eastern, mid-Atlantic, and mid-western states. Early blight in upstate New York typically occurs between the middle and end of July, and in central Pennsylvania between mid-July and mid-August. Weather conditions are generally favorable for disease development, resulting in plant defoliation in excess of 60% in the unsprayed control plots. EB occurs annually throughout PA. In the absence of fungicide use, yield loss is estimated at 30% and fruit size reduction is estimated at 10%. From five to 10 fungicide applications are typically needed to control EB in PA. NE style plants, with limited foliage, concentrated fruit set and early maturity, are more susceptible to EB.
Stakeholder concerns. The Vegetable IPM Working Group of the Northeastern IPM Center created a list of prioritized IPM needs for NE vegetable commodities (http://northeastipm.org/work_vegepriority.cfm). Members of the panel represented nine northeastern states, and Stakeholders represented by this group include growers, crop consultants, processors, departments of agriculture, university researchers and extension specialists, and environmentalists. The evaluation of the situation as pertains to late blight and early blight is summarized in Table 1.
Table 1. Evaluation of damage and control of Phytophthora and early blight on solanaceous crops, excerpted from http://northeastipm.org/work_vegepriority.cfm
Influence on Pesticide Region Crops Affected Influence on Quality/ Yield Availability of Control Pesticide Use Patterns Concern Phytophthora of all the cucurbits, beans, and solanaceous crops. Fungal pathogens (like early blight) on solanaceous crops. Region: 1 – only a limited region; 2 parts of the region; 3 across the entire region
Crops Affected: 1 few; 2 many; 3 most
Influence on Crop Yield/Quality: 1, some loss in yield and quality; 2 significant reductions in quality or yield for part of the season; 3 historically devastating crop loss in one or more crop
Availability of Controls: 1 adequate; 2 some; 3 few; none, or cost prohibitive
Pesticide Use Patterns: 1 low; 2 medium; 3 high
Clearly, both LB and EB were identified, on a regional basis, for their importance for tomato production. Similarly, calls for research dealing with the need for resistance to both diseases were released in the last 3 years (see below). In short, there is a growing call for the developing more effective LB and EB control strategies with less reliance on pesticides.
· 2005 NYS IPM program call for proposals (http://www.nysipm.cornell.edu/grantspgm/rfp_ag/03rfp/index.html): includes Breeding for resistance to multiple disease of tomato; Demonstration/research projects using TOMCAST forecasting system for tomatoes.
· Call for proposals by the Pennsylvania Vegetable Marketing and Research Program in cooperation with the Pennsylvania Vegetable Growers Association for research grants for 2005. Special priority will be given to projects involving the state's three major processing crops, namely snap beans, tomatoes, and sweet corn. Especially for tomato, disease control – late blight; bacterial canker and spot prevention and control; resistant varieties.
· At a recent Tomato IPM Workshop held with commercial growers, diseases which growers listed as most important were early and late blight of tomatoes (IPM Workshops, Cornell Cooperative Extension, 2003).
The current methods of control. Measures used for LB and EB in tomatoes have involved the use of some cultural practices, but most current control measures rely upon heavy fungicidal usage. For LB, cultural controls include the avoidance of introduction of inoculum from nearby potato cull piles, avoidance of introducing inoculum from transplant (tomato and petunia) production regions, and alerting home gardeners to use control measures to prevent home gardens from being an inoculum source for commercial growers. Cultural practices for EB control include: crop rotations of at least 2 years out of susceptible crops; use of disease-free tomato transplants; elimination of volunteer tomato and potato plants in and around the field before crop establishment; maintaining good host vigor via adequate fertilization; and beginning a fungicide spray program at first sign of disease. Chemical control measures can be an effective means of managing both diseases, and are usually guided by forecasts of blight-favorable weather conditions, but chemical applications are both time- and cost-dependent, and may be of reduced efficacy if weather conditions are particularly conducive for the disease. LB and EB control has relied upon protectant fungicides and systemic products. Fungicide sprays add a great financial burden to growers. In PA, for example, the average cost of each spray is about $20 per acre, for a total of $200 per season (average of 10 sprays per season). That adds up to over $1,000,000 per year in just one state, which when extrapolated over the entire county, is a tremendous expense to growers, consumers, and to the economy.IPM specialists today advise crop producers to choose those labeled and efficacious pesticides having the lowest possible environmental impact quotient (EIQ). It is interesting to note, that although new chemistry is much safer to the applicator and to the environment, the ‘reduced risk’ fungicides such as cymoxanil, dimethomorph, famoxadone, propamocarb, and zoxamide, need to be tank mixed with protectant fungicides in order to prevent the development of fungicide resistance. Protectant fungicides commonly used on fresh market tomatoes include chlorothalonil, copper, maneb and mancozeb, all of which have much higher EIQs than the ‘reduce risk’ fungicides.
The future method of control. We have now completed two years of testing (2002-2003) the L. hirsutum-derived EBR and with fixed resistance for LB as part of our NYS IPM trials, with funding from the USDA-CAR program. We confirmed that incorporating EBR should be homozygous, rather than heterozygous, in order for the resistance gene to express optimal level of disease control. Heterozygous hybrids were just not sufficiently resistant under severe disease pressure (light phenotype of A. tomatophila) experienced in our 2003 trials. We demonstrated that lines homozygous for the EBR can control EB with less fungicide or with the use of milder control agents (biologicals and OMRI approved materials), and that these lines homozygous for the LB resistance, can controlled LB without any fungicide applications. These results were confirmed again in 2004, when, without any added fungicide protection, and testing under the most severe weather conditions, and with the most virulent isolate of A. tomatophila, the homozygous lines had less than 20% defoliation while the comparable susceptible lines had 80% defoliation. The resistance lines showed no stem lesions, and the fruit remain healthy till the end of September. No LB infection occurred despite being present on susceptible checks in adjoining rows.
Our goal is to finalize the development of the tomato lines possessing resistance to LB and EB, then to test the best of these lines under traditional and organic growing systems. This work will result in the development of a coordinated total disease control program for NE tomato production using the genetic resistance to provide more reliable disease control and also significantly reduce reliance on chemical control. We have assembled a team of experts and have the willing support and enthusiasm of growers in both New York and Pennsylvania. We anticipate speedy adoption by stakeholders in the Northeast and beyond.
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