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Abstract
Activated charcoal was applied as a spot treatment on soil surface over the seed of watermelon [Citrullus lanatus (Thunb.) Matsum & Nakai, cv. Charleston Gray]. Planting and charcoal application were done simultaneously with specially developed equipment. Activated charcoal at 358 kg/ha fully protected watermelon from terbacil (1.12 kg/ha) injury but provided only partial protection from atrazine (2.24 kg/ha) injury. Spot application of activated charcoal did not result in decreased weed control.
Abstract
In field tests conducted near Tifton, Georgia, soil fumigation with either a methyl bromide-chloropicrin mixture (67-33%, 480 kg/ha) or metham (748 liters/ha) decreased weed infestation and increased growth and marketable yields of pepper (Capsicum annuum L.) transplants, compared with pepper planted consecutively without fumigation. Alternate-year rotation of pepper with rye also reduced weed infestation and increased yield. Weed control accounted for 81% of marketable transplant yield. Xanthomonas vesicatoria (Doidge) Dows. overwintered in pepper debris incorporated fresh or dried. Bacterial spot occurred too erratically to permit any conclusions except that the methyl bromide-chloropicrin fumigation failed to provide any control.
Abstract
Container-grown Chinese holly (Ilex cornuta Lindl. Paxt. cv. Burfordii) and Japanese holly (Ilex crenata Thunb. cv. Helleri) were treated with 6 preemergence herbicides: alachlor [2-chloro-2’,6’-diethyl-N-(methoxymethyl) acetanilide], napropamide [2-(α-naphthoxy)-N,N-diethylpropionamide], oryzalin (3,5-dinitro-N 4,N 4-dipropylsulfanilamide), and oxadiazon [2-tert-butyl-4(2,4-dichloro-5-isopropoxyphenyl)-Δ2-1,3,4-oxadiazolin-5-one] at 2.2, 4.5, 9.0, and 17.9 kg/ha; oxyfluorfen [2-chloro-1-(3-ethoxy-4-nitrophenoxy)-4-(trifluoromethyl)benzene] at 1.1, 2.2, 4.5, and 9.0 kg/ha; and prodiamine [2,4-dinitro-N 3,N 3-dipropyl-6-(trifluoromethyl)-1,3-benzenediamine] at 4.5, 9.0, and 13.4 kg/ha. All herbicides at all rates significantly reduced the number and weight of weeds as compared to unweeded checks but higher rates were more effective. Lower rates of herbicides failed to control Pennsylvania bittercress, yellow wood sorrel, and purple nutsedge. Oryzalin at 9.0 and 17.9 kg/ha was phytotoxic to both hollies. Generally, Chinese holly was more tolerant to herbicides than Japanese holly. Oryzalin was most phytotoxic to Chinese holly and substantially reduced the growth and marketability of the plants. Oxyfluorfen at 9.0 kg/ha severely retarded the growth of Japanese holly.
Abstract
Alachlor [2-chloro-2’,6’-diethyl-N-(methoxymethyl)acetanilide], napropamide [2-(α-naphthoxy-N,N-diethylpropionamide], oryzalin [3,5-dinitro-N 4, N4 -dipropylsulfanilamide], oxa-diazon [2-terr-butyl-4-(2,4-dichloro-5-isopropoxyphenyl)-∆2-l,3,4-oxadiazolin-5-one], each at 2.2, 4.5, 9.0 and 17.9 kg/ha, oxyfluorfen [2-chloro-l-(3-ethoxy-4-nitrophenoxy)-4-(trifluoro-methyl) benzene] at 1.1, 2.2, 4.5 and 9.0 kg/ha and prodiamine [2,4-dinitro-N 3, N3 -dipropyl-6-(trifluoromethyl)-l,3-benzenediamine] at 4.5, 9.0 and 13.4 kg/ha were evaluated for weed control and phytotoxicity in container-grown azaleas, Rhododendron indicum (L.) Sweet. ‘Formosa’ and Rhododendron obtusion (Lindl.) Planch. ‘Coral Bells’. All herbicides at all but the lowest rates effectively controlled grasses and broadleaved weeds. All herbicides at 9.0 kg/ha or higher rates were phytotoxic to these azaleas and restricted growth, root development and marketability. ‘Coral Bells’ was more susceptible to herbicide treatments than ‘Formosa’. Both azaleas were highly susceptible to oxyfluorfen.
Abstract
Oxadiazon was applied conventionally as a granular and compared to the emulsifiable concentrate injected into sprinkler irrigation system (chemigation) at 60- day intervals on 20 species of container-grown ornamentals. In general, phytotoxicity increased proportional to the number of applications and was most prevalent during cold weather. Moderate to severe phytotoxicity at 2 × and 4 × rates was observed on aucuba (Aucuba japonica Thunb.), azalea [Rhododendron (AZ) ‘Formosa’ and R. (AZ) ‘Fashionaire’], liriope [Liriope muscari (Decne) L. H. Bailey], pampas grass [Cortaderia selloana (Schult. & Schult. f.) Asch. & Graebn.], Japanese black pine (Pinus thunbergiana Franco), and red tip photinia (Photinia ‘Fraseri’ Dress). Increased injury was observed on aucuba, Japanese black pine, and azalea when oxadiazon was applied via chemigation. On the other species, the degree of phytotoxicity was proportional to the rate applied. Both monocots showed moderate (18%) to severe (45%) injury. The only cultivar with significant growth reductions after 8 months was the ‘Formosa’ azalea when chemigated. The only species with reduced marketability due to the herbicide was liriope. After the second application, the weight and number of weeds decreased proportional to the herbicide rate or number of applications. Chemical name used: 3-[2,4-dichloro-5-(1-methylethoxy)phenyl]-5-(1,1-dimethylethyl)-1,3,4-oxadiazol-2(3H)-one (oxadiazon).
Abstract
Combination treatments containing an organic phosphate or carbamate nematicide, a herbicide, and a fungicide on a common granule controlled root-knot nematodes and weeds and increased tomato (Lycopersicon esculentum Mill.) plant growth. Bay 68138 4 + diphenamid, ethoprop + diphenamid, Bay 68138 + pebulate + Dexon, fensulfothion + isopropalin + Dexon, Bay 68138 + isopropalin + Dexon, and ethoprop + isopropalin + Dexon completely controlled root-knot nematodes. Isopropalin and pebulate controlled FL pusley and crabgrass as effectively as diphenamid, the standard herbicide. Ethoprop + pebulate, fensulfothion + pebulate + Terrazole, ethoprop + pebulate + Dexon, and Bay 68138 + pebulate + Dexon were phytotoxic to tomato seedlings early in the growing season. Formulations containing a nematicide + herbicide + fungicide can be spread on the soil surface just before planting and incorporated with a power-driven rototiller to reduce unit production costs of tomato transplants. Production of uniform transplants free of nematodes and relatively free of weeds can facilitate mechanical harvesting.
Abstract
Disc tillage of turnip greens (Brassica campestris L. Rapifera group) caused an abrupt increase in soil strength below tillage depth, which in turn prevented turnip root penetration. Soil strength of 85 N/cm2 on Lakeland sand and 100 N/cm2 on Tifton sandy loam prevented penetration of turnip roots. In general, root fresh and dry weights were unaffected by tillage treatments. Turnip root growth with the disc treatment was shallow, whereas turnips grown with subsoil-bed and subsoil-plant tillages developed deeper root systems. Balanced downward and horizontal turnip root systems were developed with mold-board plow preplant tillage.
Abstract
Preplant tillage treatments influenced growth and yield of turnip greens (Brassica campestris L. Rapifera group). Yields in response to moldboard plow, subsoil-bed and subsoil-plant treatments were not significantly different on either Tifton sandy loam or Lakeland sand. Yields with the above tillage treatments were significantly greater than with disc treatments on Lakeland sand. However, on Tifton sandy loam, only moldboard plow treatment resulted in higher yields than with disc treatments. Plants with higher top fresh and dry weights were obtained with moldboard plow treatment on Tifton sandy loam but not on Lakeland sand. Disc treatment increased soil strength and decreased root length.
Abstract
Late blight, caused by Phytophthora infestans (Mont.) d By. was epiphytotic in several fields of tomato transplants and mature tomatoes in southern Georgia in late May of 1976. This is the first time the disease has been observed in transplant fields in southern Georgia since the 1946 late blight epidemic in the eastern United States. Preliminary fungicide tests indicated that a combination of chlorothalonil and experimental compound from Ciba-Geigy GA-1-82 at 1.12 or 0.42 kg/ha gave exceUent control for late blight. GA-1-82 very closely resembles N-(2, 6-dimethylphenyl)-N-(2-furanylcarbonyl)-L-alanine methyl ester (CGA-38140).
Abstract
This study was designed to determine the effect of pest control intensity on net returns in multiple cropping systems. The study is tempered with an evaluation of risk. The cropping system encompasses: turnip greens (Brassica rapa L.) for processing, field corn (Zea mays L.), and southern peas [Vigna unguiculata (L.) Walp. ssp. unguiculata] for processing. Within the ranges of pest control intensities studied, less intensive control resulted in higher net returns. Further, the level of greatest pest control intensity consistently yielded negative net returns. This level, however, was less risky in terms of gross returns. Risk did not differ significantly between the other levels of pest control.