Using cover crops for control of Fusarium fruit rot in commercial pumpkin production. Christian A. Wyenandt, R. M. Ried

1. Using cover crops for control of Fusarium fruit rot in commercial pumpkin production.Christian A. Wyenandt, R. M. Riedel, L. H. Rhodes, S. G. P. Nameth, and M. A. Bennett, Dept of Plant Pathology and Horticulture and Crop ScienceThe Ohio State University Using cover crops for control of Fusarium fruit rot in commercial pumpkin production. The following presentation is a research update on the use of cover crop mulches for control of Fusarium fruit rot (FFR) in pumpkin production. Presented in part at Michigan Vegetable Expo, Grand Rapids, MI on December 10, 2002 and the Ohio Small Fruit and Vegetable Congress, Toledo, OH on January 15,2003 and Mid-Atlantic Vegetable Show, Hershey, PA on February 6, 2003. Using cover crops for control of Fusarium fruit rot in commercial pumpkin production. The following presentation is a research update on the use of cover crop mulches for control of Fusarium fruit rot (FFR) in pumpkin production. Presented in part at Michigan Vegetable Expo, Grand Rapids, MI on December 10, 2002 and the Ohio Small Fruit and Vegetable Congress, Toledo, OH on January 15,2003 and Mid-Atlantic Vegetable Show, Hershey, PA on February 6, 2003.

2. Fusarium fruit rot of pumpkin Important soil-borne fungal pathogen� Especially destructive in fields with no or short rotations�U Pick operations! Fungicides, fumigation not useful� Recommended crop rotations of 4+ years for control� Control with use of cover crop mulches� Fusarium fruit rot (Fusarium spp) is an important soil-borne pathogen of Cucurbits. Fusarium fruit rot (FFR) is often a major problem in pumpkin fields in Ohio that are grown continuously to pumpkin or rotated into pumpkin every 1 or 2 years. Roadside markets with U-Pick operations often want their pumpkin fields close to the road or market to allow easy customer access. These fields are often susceptible to FFR because of little or no pumpkin rotation. The current recommendations for control of Fusarium fruit rot (FFR) are pumpkin field rotations of 4+ years. Because the fungal pathogen is soil-borne and infects the belly (bottom) of the fruit fungicide applications do not control FFR. Symptoms always appear on the belly side of the fruit (slide 1). Lesions are circular ranging go from very small to large, as the fungus invades the fruit and lesions coalesce. Symptoms on fruit may range from brownish-tan to purplish-red, often with white to gray fungal growth that appears in center of lesions. Over the past 3 years cover crop mulches have been evaluated for use in commercial pumpkin production for the control of FFR in OH. Fusarium fruit rot (Fusarium spp) is an important soil-borne pathogen of Cucurbits. Fusarium fruit rot (FFR) is often a major problem in pumpkin fields in Ohio that are grown continuously to pumpkin or rotated into pumpkin every 1 or 2 years. Roadside markets with U-Pick operations often want their pumpkin fields close to the road or market to allow easy customer access. These fields are often susceptible to FFR because of little or no pumpkin rotation. The current recommendations for control of Fusarium fruit rot (FFR) are pumpkin field rotations of 4+ years. Because the fungal pathogen is soil-borne and infects the belly (bottom) of the fruit fungicide applications do not control FFR. Symptoms always appear on the belly side of the fruit (slide 1). Lesions are circular ranging go from very small to large, as the fungus invades the fruit and lesions coalesce. Symptoms on fruit may range from brownish-tan to purplish-red, often with white to gray fungal growth that appears in center of lesions. Over the past 3 years cover crop mulches have been evaluated for use in commercial pumpkin production for the control of FFR in OH.

3. Fusarium fruit rot of pumpkin� Most infections of fruit occur in region that is in direct contact with soil. Fungus may penetrate directly under moist conditions or through wounds. Large numbers of conidia produced on field-culled or unharvested fruit!! Many ssp. reported to be seed-borne� Weedy fields may enhance FFR! In general, Fusarium fruit rot (FFR) is a soil-borne fungal pathogen that survives as a saprobe living off of dead and dying plant tissues. Interestingly, FFR has caused damage in fields that have never been in pumpkin production! Infections occur on the belly side of fruit that is in direct contact with soil, infected seed or old fruit infections. The fusarium fungus may penetrate fruit directly or more importantly through wounds in fruit. It is not known when fruit infections occur during the growing season. However, symptoms do appear on maturing (green) fruit. At least 10 Fusarium spp. are associated with fruit rot of cucurbits. Large numbers of spores are produced on infected fruit in field during the growing season and can be splashed dispersed between fruit and back into soil where it can survive between crops. Many Fusarium spp. are reported to be seed-borne. Seed purchased from a seed company won�t be infected. However, infected fruit left in field may act as a source for primary inoculum in future years. Seed from infected fruit may be spread around field during cultivation. The fungus may carry-over year to year from infected fruit and from rogue plants if seed from infected fruit germinate the next growing season. FFR seems to be more prevalent in weedy fields!!! Weedy fields may provide a canopy which enhances the microclimate for FFR development.In general, Fusarium fruit rot (FFR) is a soil-borne fungal pathogen that survives as a saprobe living off of dead and dying plant tissues. Interestingly, FFR has caused damage in fields that have never been in pumpkin production! Infections occur on the belly side of fruit that is in direct contact with soil, infected seed or old fruit infections. The fusarium fungus may penetrate fruit directly or more importantly through wounds in fruit. It is not known when fruit infections occur during the growing season. However, symptoms do appear on maturing (green) fruit. At least 10 Fusarium spp. are associated with fruit rot of cucurbits. Large numbers of spores are produced on infected fruit in field during the growing season and can be splashed dispersed between fruit and back into soil where it can survive between crops. Many Fusarium spp. are reported to be seed-borne. Seed purchased from a seed company won�t be infected. However, infected fruit left in field may act as a source for primary inoculum in future years. Seed from infected fruit may be spread around field during cultivation. The fungus may carry-over year to year from infected fruit and from rogue plants if seed from infected fruit germinate the next growing season. FFR seems to be more prevalent in weedy fields!!! Weedy fields may provide a canopy which enhances the microclimate for FFR development.

4. Typical symptoms of FFR on mature pumpkin fruit. Lesions are circular ranging from very small to large and eventually coalesce as fruit rot progresses. Symptoms on fruit may range from brownish-tan to purplish-red, often with white to gray fungal growth that appears in center of lesions. Soil often sticks to fruit where lesions are present. Fruit infection by FFR may allow secondary fungi and bacteria to infect fruit.Typical symptoms of FFR on mature pumpkin fruit. Lesions are circular ranging from very small to large and eventually coalesce as fruit rot progresses. Symptoms on fruit may range from brownish-tan to purplish-red, often with white to gray fungal growth that appears in center of lesions. Soil often sticks to fruit where lesions are present. Fruit infection by FFR may allow secondary fungi and bacteria to infect fruit.

5. Typical symptoms of FFR on mature pumpkin fruit. Often FFR will appear as a dry rot on pumpkin fruit. Temperature, rainfall and relative humidity will determine if fruit rot acts more like a dry rot or more like a wet rot. The white fuzzy growth in lesions are macroconidia of the fungus which are splashed dispersed back into the soil.Typical symptoms of FFR on mature pumpkin fruit. Often FFR will appear as a dry rot on pumpkin fruit. Temperature, rainfall and relative humidity will determine if fruit rot acts more like a dry rot or more like a wet rot. The white fuzzy growth in lesions are macroconidia of the fungus which are splashed dispersed back into the soil.

6. Why fungicides may never be useful for controlling FFR. The pictures above are a good example of why fungicides may never be useful for controlling FFR. Note how part of fruit is missed by fungicide (on right) that was covered up by canopy!!Why fungicides may never be useful for controlling FFR. The pictures above are a good example of why fungicides may never be useful for controlling FFR. Note how part of fruit is missed by fungicide (on right) that was covered up by canopy!!

7. Weedy fields may enhance FFR development. Observations over the past 3 years have shown that FFR seems to be more prevalent in weedier fields. Weeds populations may create an environment that is ideal for fungal development by keeping soil and fruit wetter longer into the day, and by keeping temperatures ideal for FFR development.Weedy fields may enhance FFR development. Observations over the past 3 years have shown that FFR seems to be more prevalent in weedier fields. Weeds populations may create an environment that is ideal for fungal development by keeping soil and fruit wetter longer into the day, and by keeping temperatures ideal for FFR development.

8. Late-season field with high weed population. FFR was prevalent in this field in 2001. Note how infected fruit were left in field after harvest. Infected fruit left in field may act as sources of inoculum (fungus) in the future. This may be extremely important if pumpkins are grown in this field the next growing season.Late-season field with high weed population. FFR was prevalent in this field in 2001. Note how infected fruit were left in field after harvest. Infected fruit left in field may act as sources of inoculum (fungus) in the future. This may be extremely important if pumpkins are grown in this field the next growing season.

9. Use of plastic mulch will not prevent fruit from FFR infection. The use of black plastic mulch in this U-Pick field was used to help control weeds. Black plastic mulch had no affect on development of FFR. Note how farmer left infected fruit in field after U-Pick operation had ceased.Use of plastic mulch will not prevent fruit from FFR infection. The use of black plastic mulch in this U-Pick field was used to help control weeds. Black plastic mulch had no affect on development of FFR. Note how farmer left infected fruit in field after U-Pick operation had ceased.

10. Why use cover crops? Add OM back to soil� Reduce erosion� Control weeds� Conserve soil moisture� Control soil-borne disease� Increase fruit cleanliness/quality at harvest� Cover crop mulch acts as physical barrier preventing fruit from coming into contact with the soil surface� Not without their disadvantages� Why use cover crops? Traditionally, cover crops serve several purposes. Farmers have used cover crops in pumpkin production to increase or add back organic matter (OM) to their soils, help reduce run-off and soil erosion, help control/reduce weed populations, help conserve soil moisture and possibly help control soil-borne fungal disease. Other potential benefits of cover crops include increasing fruit quality/cleanliness of harvested fruit. This is especially important if fruit must be cleaned prior to sale (ie. retail pumpkins). The use of cover crops in pumpkin production is not without disadvantages. Longer production schedules, extra costs and labor must be evaluated carefully by the grower prior to incorporating covers crops into production systems. Cover crops are not a cure to any particular problem, but may be an added benefit to the grower. Chemicals, such as fungicides and herbicides will still need to be used in conjunction with cover crops. In this study fall-sown (herbicide-kill), spring-sown (herbicide kill), and spring-sown (living) cover crop mulches were evaluated for their effects on pumpkin yield, fruit cleanliness and Fusarium fruit rot. For additional information on seeding rates, production schedules and using cover crops mulches please see: Update on the use of cover crop mulches in production � 2003.Why use cover crops? Traditionally, cover crops serve several purposes. Farmers have used cover crops in pumpkin production to increase or add back organic matter (OM) to their soils, help reduce run-off and soil erosion, help control/reduce weed populations, help conserve soil moisture and possibly help control soil-borne fungal disease. Other potential benefits of cover crops include increasing fruit quality/cleanliness of harvested fruit. This is especially important if fruit must be cleaned prior to sale (ie. retail pumpkins). The use of cover crops in pumpkin production is not without disadvantages. Longer production schedules, extra costs and labor must be evaluated carefully by the grower prior to incorporating covers crops into production systems. Cover crops are not a cure to any particular problem, but may be an added benefit to the grower. Chemicals, such as fungicides and herbicides will still need to be used in conjunction with cover crops. In this study fall-sown (herbicide-kill), spring-sown (herbicide kill), and spring-sown (living) cover crop mulches were evaluated for their effects on pumpkin yield, fruit cleanliness and Fusarium fruit rot. For additional information on seeding rates, production schedules and using cover crops mulches please see: Update on the use of cover crop mulches in production � 2003.

11. Quantity vs. Quality of cover crop Which is better or of more value? Quantity � species, seeding rate, time of kill Quality � species, stand uniformity, method of planting and method of kill (rolling vs mowing) Both really go hand in hand and relate to a cover crops holding capacity, or its potential to produce (quantity) and maintain ground cover (quality) during the duration of the growing season!! Quantity vs. Quality of Cover Crop. Which is better? The type of plant species used will have a dramatic effect on both quantity and quality of a cover crop. Both quantity (ie. biomass produced from a cover crop) and quality (uniformity) of a cover crop mulch will have a large impact on its value. The quantity (biomass production) of a cover crop will depend highly on the seeding rate of a particular cover crop, how and when it was established (ie. early or late fall, spring-sown) and time it was killed (early vs late spring). The quality of cover crop will depend on stand uniformity, method of seeding (broadcasting vs drilling) and method of kill (with herbicides, flail mowing, or roll chopping). For example, the seeding rate of a fall-sown cover crop, such as rye, may be less if it is sown early (50 lb/A) verses late (90 lb/A) in the fall. The time of cover crop kill (early vs late spring) will also have a huge impact on the quantity of cover crop produced. The more biomass a cover crop produces before kill the better likelihood of a higher % of ground cover and a higher % of clean fruit present at pumpkin harvest. Killing a cover crop, such as fall-sown rye, too early in the spring will affect its quantity and quality greatly diminish its holding capacity, or its ability to produce (quantity) and maintain ground cover (quality) during the duration of the growing season. Killing a rye mulch too early will ultimately reduce its potential to hold biomass and soil moisture, hold weed pressure down, and increase % clean fruit at harvest. The holding capacity of a cover crop mulch is probably most directly related to its carbon:nitrogen ratio (C:N). Cover crops with high C:N ratio, such as winter rye will breakdown much slower than cover crops with lower C:N ratios, such as spring oat and hairy vetch.Quantity vs. Quality of Cover Crop. Which is better? The type of plant species used will have a dramatic effect on both quantity and quality of a cover crop. Both quantity (ie. biomass produced from a cover crop) and quality (uniformity) of a cover crop mulch will have a large impact on its value. The quantity (biomass production) of a cover crop will depend highly on the seeding rate of a particular cover crop, how and when it was established (ie. early or late fall, spring-sown) and time it was killed (early vs late spring). The quality of cover crop will depend on stand uniformity, method of seeding (broadcasting vs drilling) and method of kill (with herbicides, flail mowing, or roll chopping). For example, the seeding rate of a fall-sown cover crop, such as rye, may be less if it is sown early (50 lb/A) verses late (90 lb/A) in the fall. The time of cover crop kill (early vs late spring) will also have a huge impact on the quantity of cover crop produced. The more biomass a cover crop produces before kill the better likelihood of a higher % of ground cover and a higher % of clean fruit present at pumpkin harvest. Killing a cover crop, such as fall-sown rye, too early in the spring will affect its quantity and quality greatly diminish its holding capacity, or its ability to produce (quantity) and maintain ground cover (quality) during the duration of the growing season. Killing a rye mulch too early will ultimately reduce its potential to hold biomass and soil moisture, hold weed pressure down, and increase % clean fruit at harvest. The holding capacity of a cover crop mulch is probably most directly related to its carbon:nitrogen ratio (C:N). Cover crops with high C:N ratio, such as winter rye will breakdown much slower than cover crops with lower C:N ratios, such as spring oat and hairy vetch.

12. Determining the quality of a cover crop by mulch measuring % ground Cover % Ground cover may be defined as the percentage of soil surface covered by mulch. The easiest way to determine (%GC) in your field is to visually rate given area(s), such as a square ft. or meter. Rating different areas in your field will help determine the quality of the cover crop. Determine overall %GC by determining the average for rated areas. The more areas visually rated the better. Determining the quality of a cover crop mulch by measuring % ground cover. The quality of a cover crop is directly related to the amount of soil covered by the cover crop mulch. In general, the higher the quality of a cover crop the higher the % ground cover (%GC). Percent ground cover can be determined by visually rating a given area (ie. square ft. or meter). This can easily be accomplished with a yard or meter stick. By visually rating different areas in the field you can determine overall cover crop quality by evaluating % GC. Determining the quality of a cover crop mulch by measuring % ground cover. The quality of a cover crop is directly related to the amount of soil covered by the cover crop mulch. In general, the higher the quality of a cover crop the higher the % ground cover (%GC). Percent ground cover can be determined by visually rating a given area (ie. square ft. or meter). This can easily be accomplished with a yard or meter stick. By visually rating different areas in the field you can determine overall cover crop quality by evaluating % GC.

13. % Ground cover of cover crop vs. % clean fruit at harvest. In general, as %GC of cover crop increases so does % fruit cleanliness. Cover crop species will have a dramatic effect on the amount of biomass present at harvest. Fall-sown winter rye will produce more biomass than spring-sown oat or hairy vetch and will last much longer during the growing season. Even without a cover crop present fruit cleanliness can be on average from 15- 25% on bare soil. % Ground cover of cover crop vs. % clean fruit at harvest. In general, as %GC of cover crop increases so does % fruit cleanliness. Cover crop species will have a dramatic effect on the amount of biomass present at harvest. Fall-sown winter rye will produce more biomass than spring-sown oat or hairy vetch and will last much longer during the growing season. Even without a cover crop present fruit cleanliness can be on average from 15- 25% on bare soil.

14. Determining the quantity of a cover crop by measuring biomass (dry wt) The quantity of cover crop mulch ( T/A) produced may be determine by weighing given area(s) such as square ft. or square meter in your field. By weighing biomass (dry wt) you will be able to determine the quantity of cover crop in your field. Determining quantity of a cover crop mulch by measuring biomass (dry wt). The quantity of a cover crop mulch may be determined by sampling and weighing a given area(s) such as a square foot or meter at any time during the production season. This means a farmer may periodically check how much biomass his cover crop has produced during the spring prior to kill. To do this one needs to take a 2x4 board of a given length,such as a yard or meter, to the field and roll it with his foot to knock down the cover crop. Use the 2x4 board as a gauge and remove the flattened cover crop with hand pruners. Place the cover crop in a paper bag and allow it to dry out in a warm area; then weigh it. This would also be a good time to evaluate % ground cover. Before removing the mulch visually rate the ground cover to see how much of the soil surface it covers.Determining quantity of a cover crop mulch by measuring biomass (dry wt). The quantity of a cover crop mulch may be determined by sampling and weighing a given area(s) such as a square foot or meter at any time during the production season. This means a farmer may periodically check how much biomass his cover crop has produced during the spring prior to kill. To do this one needs to take a 2x4 board of a given length,such as a yard or meter, to the field and roll it with his foot to knock down the cover crop. Use the 2x4 board as a gauge and remove the flattened cover crop with hand pruners. Place the cover crop in a paper bag and allow it to dry out in a warm area; then weigh it. This would also be a good time to evaluate % ground cover. Before removing the mulch visually rate the ground cover to see how much of the soil surface it covers.

15. % Ground cover vs. biomass dry wt (T/A) of cover crop mulch at harvest. In general, percent ground cover (%GC) tends to increase with increasing amount of biomass. In other words, the more biomass present at pumpkin harvest the higher likelihood of better %GC during the production season. This is extremely important when it comes to increasing fruit cleanliness at harvest. As you can see from the lower left of the graph, low amounts of biomass at harvest lessen the likelihood of % GC. To get the most out of ground cover an adequate amount of cover crop biomass must be produced prior to cover crop kill and pumpkin planting! Highlighted in green are the average amounts of biomass at harvest for bare (soil), spring-sown annual medic (AM) @ 40 lb/A, spring-sown oat (Sp. Oat) @ 110 lb/A, and fall-sown rye @ 50 and 90 lb/A, and rye+hairy vetch (Rye+HV) @ 50 lb/A ea. Average percent GC at harvest for winter rye (50 and 90 lbs/A) and winter rye + hairy vetch (Rye+HV) was 84-88%. % GC at harvest for spring-sown oat (110 lb/A) was 43% and for HV (50 lb/A) was 33%. From the graph you can see that when hairy vetch (50 lb/A) was sown alone the average %GC was only 33% at harvest suggesting that hairy vetch alone does not adequately produce enough biomass to last season long. However, when mixed with winter rye the % GC increases substantially at harvest. Spring-sown oat (110 lb/A) does not produce as much biomass as a fall-sown rye and breaks down much faster (ie. lower holding capacity) during the growing season thus its ability to produce a season long ground cover is intermediate. % Ground cover vs. biomass dry wt (T/A) of cover crop mulch at harvest. In general, percent ground cover (%GC) tends to increase with increasing amount of biomass. In other words, the more biomass present at pumpkin harvest the higher likelihood of better %GC during the production season. This is extremely important when it comes to increasing fruit cleanliness at harvest. As you can see from the lower left of the graph, low amounts of biomass at harvest lessen the likelihood of % GC. To get the most out of ground cover an adequate amount of cover crop biomass must be produced prior to cover crop kill and pumpkin planting! Highlighted in green are the average amounts of biomass at harvest for bare (soil), spring-sown annual medic (AM) @ 40 lb/A, spring-sown oat (Sp. Oat) @ 110 lb/A, and fall-sown rye @ 50 and 90 lb/A, and rye+hairy vetch (Rye+HV) @ 50 lb/A ea. Average percent GC at harvest for winter rye (50 and 90 lbs/A) and winter rye + hairy vetch (Rye+HV) was 84-88%. % GC at harvest for spring-sown oat (110 lb/A) was 43% and for HV (50 lb/A) was 33%. From the graph you can see that when hairy vetch (50 lb/A) was sown alone the average %GC was only 33% at harvest suggesting that hairy vetch alone does not adequately produce enough biomass to last season long. However, when mixed with winter rye the % GC increases substantially at harvest. Spring-sown oat (110 lb/A) does not produce as much biomass as a fall-sown rye and breaks down much faster (ie. lower holding capacity) during the growing season thus its ability to produce a season long ground cover is intermediate.

16. % Clean fruit vs. Biomass dry wt (Tons/A) of a cover crop mulch at harvest. In general, as biomass dry weight (T/A) at harvest increases so does the potential for clean fruit. Again the percentage of clean fruit at harvest will be determined by the quantity and quality (holding capacity) of the cover crop mulch.% Clean fruit vs. Biomass dry wt (Tons/A) of a cover crop mulch at harvest. In general, as biomass dry weight (T/A) at harvest increases so does the potential for clean fruit. Again the percentage of clean fruit at harvest will be determined by the quantity and quality (holding capacity) of the cover crop mulch.

17. Effects of cover crop mulch on development of Fusarium fruit rot in pumpkin production. The following slides show the relationship between above ground biomass and % ground cover of cover crops on increasing fruit cleanliness and reducing Fusarium fruit rot of pumpkin in Wooster, OH in 2002. On left, typical symptoms of FFR on bellyside of pumpkin fruit. Note how soil sticks to fruit and lesions with white fungal growth. On right, a clean pumpkin that was grown on winter rye cover crop mulch. The following slides show the relationship between above ground biomass and % ground cover of cover crops on increasing fruit cleanliness and reducing Fusarium fruit rot of pumpkin in Wooster, OH in 2002. On left, typical symptoms of FFR on bellyside of pumpkin fruit. Note how soil sticks to fruit and lesions with white fungal growth. On right, a clean pumpkin that was grown on winter rye cover crop mulch.

18. % clean fruit vs. % ground cover at harvest in Wooster, OH in 2002. As % ground cover increases so does the percentage of clean fruit. From the graph you can see that rye (50 and 90 lb/A) and rye+hairy vetch (50 lb/A ea) have a high % of ground cover (85-89%) at harvest. This on average results in a higher percentage of clean fruit (73-80%) at harvest. Percent ground cover for spring oat (110 lb/A) at harvest was 49% with an average of 45% clean fruit. Hairy vetch (50 lb/A) had an average % ground cover at harvest of 19% with 28% clean fruit. Annual medic (AM) varieties % ground cover at harvest was 1% with % clean fruit range of 7-14%.% clean fruit vs. % ground cover at harvest in Wooster, OH in 2002. As % ground cover increases so does the percentage of clean fruit. From the graph you can see that rye (50 and 90 lb/A) and rye+hairy vetch (50 lb/A ea) have a high % of ground cover (85-89%) at harvest. This on average results in a higher percentage of clean fruit (73-80%) at harvest. Percent ground cover for spring oat (110 lb/A) at harvest was 49% with an average of 45% clean fruit. Hairy vetch (50 lb/A) had an average % ground cover at harvest of 19% with 28% clean fruit. Annual medic (AM) varieties % ground cover at harvest was 1% with % clean fruit range of 7-14%.

19. % Fusarium fruit rot (FFR) vs cover crop biomass in Tons/A (dry wt) at harvest in Wooster, OH in 2002. As you can see from the graph as biomass dry wt (T/A) increases the % of fruit with fusarium fruit rot decreases. The % of fruit with FFR in bare soil plots (without cover crop) ranged in average from 48-59%. The % of fruit with FFR in hairy vetch (50 lb/A) was 31%, in spring oat (110 lb/A) was 23%, and rye (50 lb/A) was 9%, rye (90 lb/A) was 5%, and rye+HV (50 lb/A ea) was 4%. Thus, the ,more cover crop biomass at harvest the less % of fruit with Fusarium fruit rot. Plotting a graph of % fruit with FFR vs. % ground cover would yield as similar looking graph with the same trend. % Fusarium fruit rot (FFR) vs cover crop biomass in Tons/A (dry wt) at harvest in Wooster, OH in 2002. As you can see from the graph as biomass dry wt (T/A) increases the % of fruit with fusarium fruit rot decreases. The % of fruit with FFR in bare soil plots (without cover crop) ranged in average from 48-59%. The % of fruit with FFR in hairy vetch (50 lb/A) was 31%, in spring oat (110 lb/A) was 23%, and rye (50 lb/A) was 9%, rye (90 lb/A) was 5%, and rye+HV (50 lb/A ea) was 4%. Thus, the ,more cover crop biomass at harvest the less % of fruit with Fusarium fruit rot. Plotting a graph of % fruit with FFR vs. % ground cover would yield as similar looking graph with the same trend.

20. % Fusarium fruit rot vs. % clean fruit at harvest in Wooster, OH in 2002. As the percentage of clean fruit increases the amount of fruit with Fusarium fruit rot decreases. Percent clean fruit in bare soil plots (no cover crop) produced 2-5% clean fruit with 48-59 % of fruit with FFR. In hairy vetch plots % clean fruit was 28% with 31% of fruit with FFR. Percentage of clean fruit for spring oat was on average 45% with 23 % of fruit with FFR. For rye (50 lb/A) % of clean fruit was 74% at harvest with 10% of fruit with FFR, in rye (90 lb/A) % clean fruit at harvest was 80% with only 5% fruit with FFR, in rye+HV (50 lb/A ea) % clean fruit at harvest was 73% with 5% of fruit with FFR.% Fusarium fruit rot vs. % clean fruit at harvest in Wooster, OH in 2002. As the percentage of clean fruit increases the amount of fruit with Fusarium fruit rot decreases. Percent clean fruit in bare soil plots (no cover crop) produced 2-5% clean fruit with 48-59 % of fruit with FFR. In hairy vetch plots % clean fruit was 28% with 31% of fruit with FFR. Percentage of clean fruit for spring oat was on average 45% with 23 % of fruit with FFR. For rye (50 lb/A) % of clean fruit was 74% at harvest with 10% of fruit with FFR, in rye (90 lb/A) % clean fruit at harvest was 80% with only 5% fruit with FFR, in rye+HV (50 lb/A ea) % clean fruit at harvest was 73% with 5% of fruit with FFR.

21. Table shows crop crop and seeding rates, average T/A, average fruit weight (lb), % ground cover (%GC) and % clean fruit (% Clean), % FFR, and % yield loss (%YL) for Wooster, OH in 2002. From the table above you can see as % ground cover (%GC) increases so does the percentage of clean fruit (% Clean). Thus, the more ground cover of a cover crop present on the soil surface at pumpkin harvest the higher the likelihood of cleaner fruit. Research has shown over the past few years that a fall-sown rye (50 or 90 lbs/A) and a fall-sown rye + hairy vetch mix (50 lb/A ea) produce the highest amount of biomass and ground cover and result in higher percentages of clean fruit at harvest. Fall-sown hairy vetch (50 lb/A) and spring-sown oat (110 lb/A) produce intermediate percent ground cover and result in lower percentage of clean fruit at harvest when compared to rye and rye + hairy vetch. From the table you can see that as %GC and % clean fruit increase the percentage of fruit with Fusarium fruit rot (%FFR) decreases! In the same regards, as % GC and % clean fruit at harvest increase, yield loss (%YL) to FFR decreases. Table shows crop crop and seeding rates, average T/A, average fruit weight (lb), % ground cover (%GC) and % clean fruit (% Clean), % FFR, and % yield loss (%YL) for Wooster, OH in 2002. From the table above you can see as % ground cover (%GC) increases so does the percentage of clean fruit (% Clean). Thus, the more ground cover of a cover crop present on the soil surface at pumpkin harvest the higher the likelihood of cleaner fruit. Research has shown over the past few years that a fall-sown rye (50 or 90 lbs/A) and a fall-sown rye + hairy vetch mix (50 lb/A ea) produce the highest amount of biomass and ground cover and result in higher percentages of clean fruit at harvest. Fall-sown hairy vetch (50 lb/A) and spring-sown oat (110 lb/A) produce intermediate percent ground cover and result in lower percentage of clean fruit at harvest when compared to rye and rye + hairy vetch. From the table you can see that as %GC and % clean fruit increase the percentage of fruit with Fusarium fruit rot (%FFR) decreases! In the same regards, as % GC and % clean fruit at harvest increase, yield loss (%YL) to FFR decreases.

22. Fuarium fruit rot in tillage strips of fall-sown winter rye (90 lb/A). A drawback in using strip-tillage with cover crop mulches in pumpkin production is the fact that a strip-tillage production system will open the soil surface exposing bare ground. This was especially noticed during harvest. Pumpkins grown in fall-sown rye cover crop mulch plot set fruit in the strip tillage rows exposing themselves to bare soil and Fusarium fruit rot. The pumpkins seen in the above slide were all laying on bare ground in the strip tillage row and had Fusarium fruit rot at harvest.Fuarium fruit rot in tillage strips of fall-sown winter rye (90 lb/A). A drawback in using strip-tillage with cover crop mulches in pumpkin production is the fact that a strip-tillage production system will open the soil surface exposing bare ground. This was especially noticed during harvest. Pumpkins grown in fall-sown rye cover crop mulch plot set fruit in the strip tillage rows exposing themselves to bare soil and Fusarium fruit rot. The pumpkins seen in the above slide were all laying on bare ground in the strip tillage row and had Fusarium fruit rot at harvest.

23. Acknowledgments Ohio Small Fruit and Vegetable Research and Development Program NCRSARE OSU Graduate Student Competitive Research Grant Program Paul C. & Enda H. Warner Endowment Fund OARDC Matching Grants Program OSU IPM Mini-Grants Program I�d like to acknowledge the following groups for their financial support of this research.I�d like to acknowledge the following groups for their financial support of this research.

24. For more information on this research or on the use of cover crops in pumpkin production please contact Andy Wyenandt, Dept. of Plant Pathology, the Ohio State University @ wyenandt.1@osu.edu or at by phone at (614) 292-9355.  If you would like more information on the use of cover crops in pumpkin production please contact Andy Wyenandt via e-mail at wyenandt.1@osu.edu or by phone at (614) 292-9355.If you would like more information on the use of cover crops in pumpkin production please contact Andy Wyenandt via e-mail at wyenandt.1@osu.edu or by phone at (614) 292-9355.