Vegetable Crops Edition
Seasonal updates and alerts on insects, diseases, and weeds impacting vegetable crops. New Jersey Commercial Vegetable Production Recommendations updates between annual publication issues are included.
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EPA Releases Temporary Guidance on Respiratory Protection for Agricultural Pesticide Handlers During COVID-19
Hand Sanitizers for Use in the Field
Under the “Interim COVID-19 Guidance for Migrant and Seasonal Farmworkers, Their Employers, and Housing Providers”, employers are required to provide hand sanitizers with at least 60-95% alcohol in various locations and employers are to schedule handwashing breaks every hour. If soap and water are not available, an alcohol-based sanitizer that contains 60-95% alcohol may be used. Hand sanitizers may be difficult to find, but a grower can make their own. Visit the onfarmfoodsafety.rutgers.edu website for a factsheet entitled “Home-made Hand Sanitizer”. This walks you through how to make a cheap effective sanitizer.
The next question is, what is the proper method to apply and use the sanitizer? Research has shown that a two-step sanitizer method is the best method for alcohol-based sanitizers.
- Step 1: Apply three pumps of sanitizer from the dispenser.
- Step 2: Rub hands for 20 seconds making sure to cover the palms, backs of hands, and between fingers up to the wrists.
- Step 3: Wipe the hands on a disposable paper towel.
- Step 4: Apply one pump of the sanitizer from the dispenser.
- Step 5: Rub hands until dry.
Hand sanitizers do not take the place of handwashing before starting or returning to work; after using the toilet; before and after eating and smoking; before putting on gloves; after touching animals or animal waste or any other time hands may become contaminated under the Food Safety Modernization Act or for most audits.
FDA Provides Flexibility to Farms Regarding Eligibility for the Qualified Exemption Under the Produce Safety Rule
The U.S. Food and Drug Administration announced that it will provide flexibility regarding eligibility criteria for the qualified exemption under the Produce Safety Rule during the COVID-19 public health emergency.
Under the FDA Food Safety Modernization Act (FSMA) Produce Safety Rule, farms are eligible for a qualified exemption and associated modified requirements if they meet certain criteria:
- The farm’s food sales averaged less than $500,000 (adjusted for inflation) per year during the previous three years; and
- The average value of the farm’s sales to qualified end-users exceeded the average value of the farm’s sales to all others during the previous three years. A qualified end-user is either (a) the consumer of the food or (b) a restaurant or retail food establishment that is located in the same state or the same Indian reservation as the farm or not more than 275 miles away.
Because of COVID-19, state and local governments across the United States have instituted public health orders that have resulted in many restaurants and retail food establishments either closing or significantly limiting their operations, leaving many farmers without their usual buyers. The guidance intends to allow affected farmers to shift their sales away from qualified end-users while still being considered eligible for the qualified exemption. Specifically, under the temporary policy announced in the guidance, farms that are currently eligible for the qualified exemption and associated modified requirements will still be considered eligible, even if they shift sales away from qualified end-users, so long as they continue to meet the requirement that their average food sales during the previous three years total less than $500,000 (adjusted for inflation).
FDA recognizes that providing flexibility to farms to allow them to shift food sales to available buyers during the COVID-19 public health emergency can help reduce food waste and food shortages. This temporary policy is intended to remain in effect only for the duration of the public health emergency, after which the FDA intends to issue additional guidance.
Qualified exempt farms must comply with modified requirements under the Produce Safety Rule, which include establishing and keeping certain records and prominently displaying their name and business address on food packaging or at the point of sale. Farms are responsible for ensuring that the food they produce is not adulterated under the Federal Food, Drug, and Cosmetic Act (FD&C Act) and they should use good agricultural practices to ensure the safety of their produce.
Residual Weed Control in Cabbage and Other Cole Crops
Good weed control in transplanted and seeded cole crops requires planning and the use of pretransplant or preemergence herbicide applications.
Cabbage treated pretransplant with Goal. The crop was never cultivated.
Preplant incorporate Treflan HFP at 1 to 1.5 pt/A for seeded and up to 2 pt/A for transplanted, or apply Dacthal 6F at 6 to 14 pt/A or Prefar 4E at 4 to 9 qt/A preemergence or post-transplant to control annual grasses and certain broadleaf weeds. Choose Dacthal or Prefar in early spring when soils are cold and wet when Treflan may cause temporary stunting. Please make sure to check the label before mixing as these herbicides are registered for use only on certain cole crops.
Goal 2XL and GoalTender 4F are labeled for transplanting ONLY!. Goal 2XL can ONLY be used pretransplant whereas GoalTender 4F can be used pre-transplant or post-emergence with a 24(c) Special Local Needs label on broccoli, cabbage and cauliflower in New Jersey (NJ 24(c) SLN GoalTender 4F). Build beds, spray, and transplant through the herbicide barrier. Use Prefar or Dacthal post-transplant for grass control. Treflan or Dual Magnum applied preplant incorporated may increase the risk Goal injury. Do NOT cultivate unless weeds appear. Incorporation of Goal reduces or eliminates the effectiveness of the product for weed control. Goal and GoalTender are registered for use only on certain transplanted cole crops.
Dual Magnum 7.62E has a 24 (c) Special Local Needs label for use on cabbage in New Jersey. Use Dual Magnum at the rate of 0.5 to 1.33 pt/A depending on soil type. Use the lower rate on soils that are relatively coarse-textured or low in organic matter; use the higher rate on soils that are relatively fine-textured or high in organic matter. Apply to weed free soil in transplanted cabbage after transplanting, or to direct seeded cabbage when the seedlings have developed 3 to 4 true leaves. The delayed use in directed seeded cabbage reduces the risk of slight temporary stunting of the crop. Dual Magnum controls annual grasses, nightshade species, and galinsoga. Yellow nutsedge will be suppressed or controlled at the rates and use patterns on the Dual Magnum label for cabbage. To obtain a label, an indemnification agreement must be filled out on line agreeing not to hold the manufacturer responsible for crop damage. Obtain a copy of the label and complete the indemnification agreement on the Syngenta website. Register or sign in, select state and product, and submit. You will then be asked to select your crop before accepting or not the waiver of liability and indemnification agreement. You must have a copy of this 24(c) label if you want to use Dual Magnum on cabbage!
Consult the 2020/2001 Mid-Atlantic Commercial Vegetable Production Recommendations for rates and additional information.
Signage for Farm Worker COVID-19 Education Available
NJ Secretary of Agriculture Douglas Fisher has requested the following message be shared with the farm community.
To assist farm operators in the provision of COVID-19 education, the NJ Department of Health has created a set of prevention messages that can be used as signage to be hung in common areas on farms. [Read more…]
Specialty Crops Injury Caused by Dicamba Herbicide Drift
Figure 1. Non-tolerant soybean foliage when exposed to a sublethal rate of dicamba 2 weeks after treatment. Leaves are cupped with the bottom edges curved towards the top surface of the leaves.
By Maggie Wasacz1 and Thierry Besancon2
1 Rutgers Weed Science Graduate Student; 2 Rutgers Weed Science Extension Specialist for Specialty Crops
Glyphosate-tolerant soybeans were first commercialized in 1996 in the United States. By 2006, almost 9 out of every 10 soybean acres were planted with glyphosate-tolerant cultivars. However, reliance on glyphosate alone for soybean weed control stimulates the selection of weed biotypes naturally resistant to glyphosate. By 2019, there were 43 weed species known to be resistant to glyphosate, including species such as Palmer amaranth or waterhemp that can easily out-compete soybean and reduce yield by more than 50% if left uncontrolled.
What is Dicamba Herbicide?
One way to control glyphosate-resistant weeds is to treat them with herbicides other than glyphosate, such as dicamba. Dicamba is a synthetic auxin herbicide that has been used to control broadleaf weeds for over 50 years. Chemical and seed companies have recently developed new soybean varieties that are tolerant to dicamba and that started to be commercialized in 2016. With the development of genetically modified dicamba-tolerant soybeans, dicamba may be sprayed more frequently during the growing season. Additionally, dicamba is regularly applied in corn, for right-of-way applications, and in the early fall for perennial weeds control.
Dicamba can injure sensitive broadleaf plants through tank incorrectly rinsed after spraying dicamba, particle drift during the dicamba application, and vaporization after dicamba has been applied . Particle drift refers to the herbicide being carried off-target by the wind during the application. Wind speed, particle droplet size, nozzle type, carrier volume, application method, and application speed will affect the extent of particle drift. Vaporization, on the other hand, occurs when the herbicide evaporates from the target plant and these vapors travel off-target. For more information on herbicide drift, please refer to the following PPA post 10-best-management-practices-to-avoid-herbicide-drift.
If some of the dicamba sprayed onto a soybean field moves off-target and lands on a nearby field planted with a sensitive crop, the results can be very harmful. This injury could potentially cause aesthetic damage as well as reduce yield reduction. Potential for yield loss is influenced by amount of dicamba as well as when the injury occurs. Small volumes of dicamba products can cause leaf cupping and deformation, plant twisting, and in extreme cases, plant death of sensitive crops.
Screening Vegetables for Dicamba Sensitivity
Greenhouse studies conducted at Rutgers University in 2019-2020 screened economically important vegetable crops from the mid-Atlantic region for sensitivity to sublethal doses of dicamba. These micro-rates of dicamba simulated varying levels of drift conditions in the field. To put the rates into perspective, the highest dose in this study was equivalent to about one drop of product per quart of water. The goals of this study are to develop recommendations that can help growers design their planting strategies around dicamba-treated fields as well as to use this data to help refine recommendations to maximize protection of sensitive crops.
Crop-Specific Reactions to Simulated Dicamba Drift
The most sensitive crops in this study were the leguminous crops, including non-tolerant soybean, lima bean, and snap bean, as well as solanaceous crops, such as tomato, eggplant and pepper. These crops demonstrated severe injury.
Soybean injury is characterized by the underside edges of the leaves curling upward toward the top surface of the leaves (Figure 1). Lima bean and snap bean have similar injury symptoms, both exhibiting injury in several ways. Higher rates caused some leaves to not emerge at all, while lower rates caused leaf cupping injury that caused the top edges of the leaves to curve downward towards the ground. Other symptoms included a bubble-like texture on the top sides of the leaves, as well as leaf crinkling.
Figure 2. Eggplant 2 weeks after treatment. The undersides of affected leaves are curled upward toward the top surfaces of the leaves.
Figure 3. Bell pepper 2 weeks after treatment. The leaves are cupped with a bubble-like texture on the top surface.
Figure 4. Tomato 2 weeks after treatment. Leaflets are curled, reduced in size, and deformed.
For eggplant and bell pepper, injury was expressed as the undersides of the leaves curling upward toward the top surface (Figures 2 and 3). Additionally, leaf crinkling is seen in bell pepper foliage (Figure 3). Finally, tomato plants express dicamba injury with leaf twisting, cupping, stunting, and crinkling. At higher rates, these leaflets will be extremely stunted and deformed (Figure 4). Lower rates will show slight cupping, leaf crinkling and a change in leaf surface texture. Among the most tolerant crops from this study were basil, pumpkin, lettuce, and kale. These plants incurred the lowest amount of damage. The moderately sensitive crops included watermelon, cucumber, and summer squash. Watermelon foliage exhibits injury differently than many of the other crops tested in the study. Rather than leaf cupping, watermelon leaf texture appears shriveled and more deeply lobed with small bubbles on the top leaf surface (Figure 5).
Figure 5. Watermelon 2 weeks after treatment. Leaves are deeply lobed with a puckering, bubble-like texture.
Figure 6. Summer squash 2 weeks after treatment. Leaf edges are curved downward toward the ground.
Figure 7. Cucumber 2 weeks after treatment. Leaf is cupped and the bottom edges of the leaf are curved upward towards the top leaf surface.
Summer squash and cucumber, however, show leaf cupping when injured. In summer squash, the top edges of the leaf curve downward towards the ground (Figure 6). The foliage of cucumber tends to curve the bottom edges upward toward the top surface of the leaf, although both directions of cupping were observed. (Figure 7).
On-Going Research at Rutgers
This summer, Rutgers researchers will select a few of these crops to take yield in a field-based dicamba drift study that tests different drift rates and application timings. Although this study gives some preliminary information, more detailed studies are necessary to confirm these findings. However, in the meantime, this greenhouse work gives us a brief snapshot of which species to be most concerned with when working near dicamba treated fields and provides help with field identification of these injury symptoms.
If you suspect that dicamba drift may have injured your crops, please contact you local county extension agent or Rutgers weed science specialist (Dr. Thierry Besançon) as soon as possible, and take detailed pictures of the observed damages.
