Questions and Answers About Vineyard Injury from Herbicide Drift

Q. Why grow if the plants are so days depending on the level of expo- herbicides including 2,4-D also may easily damaged by hormonal-type her- sure, although death may not occur delay ripening and cause uneven bicides such as 2,4-D? for several weeks or months. ripening of berries in the cluster. A. Those with an interest in agriculture may raise livestock, grow wheat or soy- Q. Are young vines more sensitive Q. Will the plants grow normally again beans, or manage an agricultural busi- to hormonal-type herbicide than the next year? ness. growers want to grow mature vines? A. Vines may or may not survive. Damage grapes because of the potentially high A. Young vines are much more suscepti- to the vines increases with higher con- return compared to other crops. ble than mature vines to hormonal- centration of hormonal-type herbicide Grapes are a legitimate and highly type herbicide such as 2,4-D. In drift and repeated exposure. Herbicide valuable food crop. addition, mature vines have the ability drift may result in loss of the current to recover more rapidly from low-level year’s grape . It may weaken the Q. But why not grow grapes in grape- exposure than young vines. vines so they are more susceptible to growing areas other than Kansas? winter injury. Grapevines damaged by A. Kansas is a good grape-growing state. Q. Will the leaves outgrow these high concentrations of hormonal-type Grapes grew naturally in Kansas before symptoms? herbicides, especially late in the grow- European settlement. Kansas ranked A. There is no definite answer. Herbicide, ing season, could continue to show among the top 10 states in grape pro- concentration, grape cultivar, age of visual symptoms the year after the ini- duction at one time. The summer tem- vine, vine vigor, and weather conditions tial damage occurred. If exposure to peratures, long growing season, and all influence recovery. With higher con- hormonal-type herbicide is light, there high light intensity are all conditions centrations, the obvious damage is evi- may be no further symptoms after the that help produce good grape crops. dent in new growth. In grapes, there initial leaf symptoms. Normal growth are several (five to eight) developing may return in the absence of hor- Q. What happens when 2,4-D drifts onto leaves in the shoot apex or tip, as well monal-type herbicide exposure if the grapevines? as three to four expanding leaves below vine is in good health. A. Hormonal-type herbicides are easily the apex. Grapes develop a canopy of absorbed and translocated in leaves from shoots arising from canes, Q. Does weather influence the extent grapevines. The injury symptoms resulting in many developing leaves on of hormonal-type herbicide injury? induced in plant species sensitive to the vine. Damage that occurs early in A. Yes, wind can be a major influence. hormonal-type herbicides are similar the season is multiplied by the pres- Spraying when it is windy is inviting to symptoms induced by natural plant ence of many growing points, reducing a lawsuit if there are grapes or other hormones. With increased dosage, the photosynthetic activity and weak- susceptible plants in the area. Wind symptoms include cupping and stunt- ening the vine. If lower concentrations velocity during herbicidal application ing of leaves, stem epinasty, and dam- of 2,4-D drift onto the vine, the imma- should be less than 10 miles per hour age to the terminal growing points. ture leaves may show injury symptoms, unless otherwise stated on the label, (For illustrations see K-State Research but leaves that emerge after exposure and in a direction away from suscepti- and Extension Publication S-142, may show little or no injury. ble plants. In addition, herbicide Preventing Hormonal-Type Herbicide sprayed in calm (no wind) conditions Damage to Kansas Grapes.) Tissue pro- A. Does hormonal-type herbicide injury may result in significant herbicide drift liferation along the length of the stem interfere with fruit or grape can result in disintegration or blockage cluster development? of phloem and xylem tissue. Leaf mal- Q. Yes, anything that interferes formation is most prominent on the with photosynthesis will affect youngest and fastest-growing leaves. fruit development. Herbicide Severe injury may kill the vines. drift may reduce fruit size and weight. It also can result in Q. How rapidly does this happen? “shot” or buckshot-size A. Hormonal-type herbicides are rapidly berries in a cluster. As the transported to merstimatic tissues, that concentration increases, so Normal cluster Grape cluster Irregular maturity is, the new growing area. Symptoms does the development of injured by 2,4-D of grape berries normally appear within a few hours or “shot” berries. Hormonal-type after 2,4-D exposure Kansas State University Agricultural Experiment Station and Cooperative Extension Service due to temperature inversion. High Q. Why do growers plant cultivars that profitable. However, careful cultivar temperatures increase the risk of vapor are easily damaged by 2,4-D? selection can help reduce the risk drift of volatile herbicides, such as 2,4- A. Some of the most susceptible cultivars of herbicide drift problems without D ester. High temperatures to 2,4-D have desirable qualities for compromising plant vigor and quality. and humidity also promote greater production and may be the most hormonal-type herbicide uptake. Table 1. Grape cultivars as affected by 2,4-D exposure. Susceptibility to Q. What is a safe distance from a vineyard 2,4-D is based on field research, experience, and observation. to spray hormonal-type herbicides? A. More than one factor is involved here. Less susceptible More susceptible Two forms of 2,4-D drift can damage grapevines. One is the drift of spray Alden droplets: Small particles can move with Baco 1 Bath Bluebell the wind, land on grapes, and be Bromariu Campbell Early absorbed into the grapevines through Buffalo the cuticle on the leaf. The distance the CAB FRA droplets drift depends on the size of the CAB SAU droplets, wind velocity, and the height Canada Muscat Canadice Concord at which the herbicide is discharged. Delaware The smaller the droplet, the farther it Chardonnay Einset will travel. The other form is vapor Foch drift. Volatile herbicides may produce Fredonia vapors that are carried several miles Edelweiss Himrod Golden Muscat form the target area. Horizon Interlaken Ives Q. What other crops beside grapes are La Crescent sensitive to hormonal-type herbicide? Leon Millot A. Legume crops, cotton, potatoes, toma- Nero Marquis Pinot Noir Mars toes, other vegetables, many broadleaf Plai ornamental trees, shrubs, and flowers. Price /Cynthiana Reliance NY Muscat Q. There are different formulations Romulus Ravat of 2,4-D and other hormonal-type Reliance Steuben Seneca herbicides. Is there a difference in Swanson Red Sheridan their potential damage? Toldi Seibel 2653 A. Yes, 2,4-D, triclopyr and clopyralid Valiant Siegfried herbicides are formulated in ester Ventura St. Pepin or amine forms. Esters are more haz- Steuben Villard blanc Sultana ardous in terms of their volatility and Vincent Seyval potential to damage sensitive crops. Thompson seedless The volatile ester formulations release Tokay vapors rapidly at about 80 degrees, there- fore, nearby applicators can reduce vapor Villard noir drift potential by choosing amine formu- Yates lations rather than ester.

Q. Are all grape cultivars (varieties) damaged equally? Kansas State University Authors: Sorkel Kadir, Fruit Scientist Agricultural Experiment Station A. No, although all grape cultivars are Kassim Al-Khatib, Weed Physiologist and Cooperative Extension Service Dallas Peterson, Weed Specialist susceptible to 2,4-D, there are differ- Manhattan, Kansas ences between grape cultivars in sus- It is the policy of Kansas State University Agricultural Experiment Station and Cooperative Extension Service that all ceptibility to 2,4-D injury. Table 1 persons shall have equal opportunity and access to its educational programs, services, activities, and materials without regard to race, color, religion, national origin, sex, age, or disability. Kansas State University is an equal opportunity shows the relative susceptibility of organization. These materials may be available in alternative formats. selected grape cultivars to 2,4-D. Issued in furtherance of Cooperative Extension Work, Acts of May 8 and June 30, 1914, as amended. Kansas State University, County Extension Councils, Extension Districts, and United States Department of Agriculture Cooperating, Marc A. Johnson, Director. MF-2588 October 2003