( Lactuca sativa L.), the predominant crop in this region ( Bottoms et al., 2012 ; Breschini and Hartz, 2002 ; Hartz et al., 2000 ; Jackson et al., 1994 ). Less attention has been given to cole crops (broccoli, cabbage, and cauliflower), which are
Fall cole crops of exceptional quality and high market value are produced in Kentucky. Tobacco is an integral part of agriculture in the southeastern states and production of fall cole crops following tobacco may increase diversification and Potential profits. A float system was utilized for transplant production. Field plots were established with broccoli and cabbage grown conventionally, planted into killed sudex cover, cultivated tobacco stubble and directly into tobacco stubble. Data were collected on soil fertility, insect and weed populations, crop quality and yield. Periodically, foliar samples were analyzed for nitrate, total nitrogen, phosphorus, potassium and calcium content. Fall cole crops grown conventionally or in killed sudex cover produced comparable results and head size. Insect pressures were reduced in killed sudex covers. Total yield and quality were reduced when seedlings where planted directly into tobacco stubble.
Cole crop [broccoli, cabbage ( Brassica oleracea var. oleracea L.), and cauliflower ( Brassica oleracea var. botrytis L.)] and leafy green [collards and kale ( Brassica oleracea var. sabellica L.)] production in the United States
Partial steam and chemical sterilization of soil rich in organic matter increased the soil nutrients, little information exists with regard to the effect of soil solarization (SS) in this regard. A study was established to determine the effects of SS in combination with wheat residue and subsequent crop residue on increased growth response (IGR) of cole crops and soil fertility for two years. SS for 90 days increased K+, P, Ca++ and Mg++ 3 times more within five months after SS. The SS effect released higher levels of total N in the soil. However, increase levels of N was lower than that required for maximum IGR of collard. The IGR of cole crops without fertilizers was higher in SS plots as compared to bare soil. The IGR of collard was evident almost two years after SS.
Over a 6-year period (1969-1974) the efficacy of 3 insecticides and 24 herbicides and their interactions in combination were investigated when applied to field-seeded broccoli (Brassica oleracea L. Italica group), cabbage (Capitata group) and cauliflower (Botrytis group). Of these, broccoli was the most susceptible to injury. Of 212 herbicide-insecticide combinations, 26 caused phytotoxic symptoms in broccoli, 20 in cabbage and 8 in cauliflower. The insecticides, thionazin, fensulfothion and carbofuran, were each involved in 1 or more phytotoxic combinations in each of the 3 crops. Ten herbicides were involved in phytotoxic reactions: alachlor, aziprotryn, benefin, CDEC, chlorpropham, cycloate, prometryne, propachlor, prynachlor and PP493. Root maggot damage was reduced markedly by the insecticides. Carbofuran allowed less damage than either fensulfothion or thionazin. None of the herbicides showed any insecticidal properties, and some decreased the effectiveness of the insecticides.
These studies were initiated to investigate severe growth inhibition observed when some vegetable crops were infested with corn spurry (Spergula arvensis L.). Interference by a natural population of the weed reduced the shoot weights of English pea (Pisum sativum L.) and collard (Brassica oleracea L.) by 93% and 72%, respectively. In a greenhouse experiment where light competition by corn spurry was prevented, broccoli (Brassica oleracea L.) shoot weights were reduced by corn spurry, but pea weights were not different from the controls. Homogenized corn spurry shoot tissue incorporated into a greenhouse potting medium inhibited the growth of both species, and a concentration effect was observed. Sequential hexane, dichloromethane, methanol, and 50% aqueous methanol extracts of corn spurry root and shoot tissue were tested for inhibitory activity using millet seed germination and broccoli seedling growth bioassays. Dichloromethane, methanol, and aqueous methanol shoot extracts were inhibitory to broccoli; whereas all shoot extracts inhibited millet germination. Shoot extracts were more inhibitory than root extracts. Further fractionation of the inhibitors using a combination of reversed-phase sephadex LH-20 and silicic acid column chromatographic procedures showed that a major portion of the millet germination inhibition was due to sucrose esters (SE). Preliminary characterization of the esters showed that there were four different SE groups. The major groups contained either octanoic or dodecanoic acid along with butanoic and petanoic acids. All groups inhibited seed germination at concentrations as low as 20 ppm. This is the first report of the SE class of defense chemicals in plant species outside of the solanaceae family.
United States, except in California where the herbicide is banned ( FMC Corp., 2005 ). However, it is not registered for the other cole crops [broccoli, brussels sprouts ( Brassica oleracea Gemmifera group), cauliflower ( B. oleracea Botrytis group
Winter production of collard and kale (Brassica oleracea L. Acephala Group) in the southeastern United States is limited by the tendency of these leafy green vegetables to bolt following vernalization. Collard and kale cultivars, landraces, and breeding lines were tested in four winter environments from 1992 to 1995 to determine differences among all included entries for winter production and tendency to bolt in a cold season environment. Essentially all entries survived the conditions of four winter environments. However, whether an entry reached harvest size depended on its date of 50% bolting. Collard typically bolted earlier than kale. Most kale entries reached a marketable size before bolting, while only the collard cultivars `Blue Max' and `Champion' and landraces G. Summersett and Mesic Zero consistently did the same. Several entries, for example, `Squire' kale and G. Summersett collard, usually did not bolt. Results of this research indicate that significant genetic control of the long-standing (delayed bolting) phenotype is present in collard and kale. Successful winter production of these cole crops can be better ensured by using a long-standing genotype.