( European Union, 2009 ). The response of plants to flaming varies according to species, growth stage, leaf surface moisture, flaming dose, and temperature of the flame and air ( Ulloa et al., 2010 ). Regardless of the growth stage, broadleaf weeds are more
Luisa Martelloni, Lisa Caturegli, Christian Frasconi, Monica Gaetani, Nicola Grossi, Simone Magni, Andrea Peruzzi, Michel Pirchio, Michele Raffaelli, Marco Volterrani and Marco Fontanelli
M. Brett Callaway
Plant breeders have successfully increased crop tolerance to many pests and physiological stresses. However, very little work has examined the potential for increasing levels of tolerance to weeds, despite weed control costs of several billion dollars annually. Evidence will be summarized from the literature supporting the contention that genotypic differences in tolerance to neighboring plants exist. Approaches to screening for tolerance, choice of selection environment, and genotype identification will be discussed.
Richard L. Parish
Flame “cultivation” for weed control was developed about 50 years ago. The practice was very popular with Southern cotton farmers through the 1950s and 1960s, but lost favor when petroleum prices rose drastically in the 1970s. There is now a new interest in the practice of flame cultivation as a partial or total replacement for herbicides in vegetable crops. This interest is fueled by three factors: 1) an increasingly negative public perception of herbicides on vegetables, 2) a very limited selection of herbicides labeled for vegetables, and 3) limited efficacy of some of the herbicides that are registered. Flame cultivation, in combination with mechanical cultivation, can replace or supplement herbicides in some vegetable crops. The mode of action of flame cultivation is the bursting of cell walls in the weeds as the weeds are heated by a carefully directed LP gas flame. With most vegetable crops, the crop plants must be protected in some manner. This can be done with a water shield (flat fan water spray), height differential between weeds and crop, physical shield, etc. Much of the early work on flame cultivation of vegetables was done with sweet corn. Work is now underway on flame cultivation of lima beans and southernpeas, where multiple flame cultivations have proven effective at controlling weeds for which no herbicide is available.
Amit J. Jhala, Analiza H.M. Ramirez and Megh Singh
7,427,000 tons in Florida ( USDA, 2012 ). Weed management is an important horticultural operation in citrus production practices. Weeds are highly competitive with citrus trees under the growing conditions of central Florida because of frequent
Daniel C. Brainard, John Bakker, D. Corey Noyes and Norm Myers
suppression of weeds ( Liebman and Dyck, 1993 ; Teasdale, 1998 ). Despite these potential benefits, living mulches have not been widely adopted in vegetable cropping systems attributable in part to their tendency to either compete directly with the crop or
Guangyao Wang and Mathieu Ngouajio
cover cropping are needed to help minimize risks like herbicide resistance and environmental contamination. Machine-harvest pickling cucumber has an average growing cycle of 40 to 55 d. Its canopy closes ≈3 to 4 weeks after emergence. Because weeds
Elsa Sánchez, William J. Lamont Jr and Michael D. Orzolek
Soil properties on organic farms favor a greater diversity in weed species and reduced weed pressure compared with conventional farms ( Ngouajio and McGiffen, 2002 ). Despite the reduced weed pressure, weeds are frequently cited as the most
Erin C. Hill, Mathieu Ngouajio and Muraleedharan G. Nair
. Pickling cucumber seeds were provided by Seminis Inc. Weeds seeds were contributed by Ruth Mangum and Karen Renner. We would like to thank Juan Pedro Steibel for his assistance in the statistical analysis of this work.
Emillie M. Skinner, Juan Carlos Díaz-Pérez, Sharad C. Phatak, Harry H. Schomberg and William Vencill
become invasive in the continental United States is small. Sunnhemp will not set seed north of 28° N latitude ( Reeves, 2007 ). Cover crops can help suppress weeds by establishing unfavorable conditions for weed growth and competing for resources ( Phatak
Rick A. Boydston, Treva Anderson and Steven F. Vaughn
, many producers hand-weed containers to ensure maximum growth of ornamentals and to keep weeds from lowering the value of the crop. The use of products derived from natural sources to control pests is appealing, and developing new uses for mustard