Potatoes problems

Mechanical displacements associated with potato are in the micron range. Quantitation of potato effects is difficult, and no perfect solution to potato problems exists. Every ESR spectroscopist is aware of the problem, and partial solutions can often be found based on the conceptual models outlined in this section. 

Up until 1986 the major use for 2-j -butylphenol was in the production of the herbicide, 2-j -butyl-4,6-dinitrophenol [88-85-7] which was used as a pre- and postemergent herbicide and as a defoHant for potatoes (30). The EPA banned its use in October 1986 based on a European study which showed that workers who came in contact with 2-j -butyl-4,6-dinitrophenol experienced an abnormally high rate of reproduction problems. Erance and the Netherlands followed with a ban in 1991. A significant volume of 2-j -butyl-4,6-dinitrophenol is used worldwide as a polymerization inhibitor in the production of styrene where it is added to the reboiler of the styrene distillation tower to prevent the formation of polystyrene (31). OSBP is used in the Par East as the carbamate derivative, 2-j -butylphenyl-Ai-methylcarbamate [3766-81-2] (BPMC) (32). BPMC is an insecticide used against leaf hoppers which affect the rice fields. 

The fact that is not radioactive means that it can be used safely in experiments in the field, but it also means that much patient work is needed to obtain results. The approach is demanding in terms of time, equipment, and skilled manpower, but it has made a great contribution to the understanding of the nitrate problem. The results that are outlined here are from experiments made by staff at Rothamsted, but key contributions have also come from Scotland and France. " The majority of the Rothamsted experiments involved winter wheat, but oilseed rape, potatoes, beans, and sugar beet were also grown. The soil is a factor in nitrate leaching, and three types were used, the flinty, silty clay loam at Rothamsted, a sandy loam at Woburn in Bedfordshire and a heavy sandy clay at Saxmimdham in Suffolk. 

The most serious disease problems encountered in organic crops are blight in potatoes and seedbome diseases in cereals. Plant breeders are improving blight resistance in potatoes. As organically grown cereal seed cannot be treated, it is very important that it is tested for seed-borne diseases such as fusarium and smut. Foliar diseases in organic... 

The fact that Germany depended on imported fertilizer more than any other country gave it a special stake in the problem, too. The industrialization of Germany s sugar beet and potato farms was intimately linked to its use of natural fertilizer, especially nitrogen compounds from marine bird manure imported from Peru, Chile, and Bolivia. Yet experts predicted that Europe would exhaust South America s guano in 30 years. 

To illustrate the problems that are faced in contemporary metabolic engineering it is worth considering two fields that have recently received much attention starch biosynthesis in potato tubers and the production of bioplastics in Arabidopsis. 

The oxidation of starch in aqueous suspension with H202 in the presence of iron phthalocyanine gives both carboxylic and carbonyl groups (Table 3.1). The best yields were obtained with a molar ratio 12900/1 (0.0078 mol%), but the oxidation was still quite efficient with 0.0039 mol% of catalyst [25800 per anhydroglucose unit (AGU)/catalyst ratio]. The oxidized starch had almost the same final Fe-content as the initial potato starch. Still, the efficiency of this method in view of scaling up was limited by comparatively low activity and product isolation problems. 

The potato is a basic food crop in the Andean region of South America, and is an important cash crop in many other sections of Latin America. The investment necessary to produce a crop is considerably higher than in the case of corn, wheat, or beans, and the potato grower is correspondingly more interested in protecting this investment wherever diseases or insects are likely to be a problem. 

Early blight, Alternaria solani Kuhn., is a problem in some areas, particularly in. warmer climates where potato growth is not optimum. Control can be obtained by protective sprays, particularly with the organics that have been recommended for late blight control. 

Clockwise from top left) Plant problems Pea plants stressed by drought and heat leaf yellowing between the veins, a common symptom of mineral deficiency red currant bush with most of its leaves stripped to skeletons by the pest gooseberry sawfly the fungal disease potato blight... 

Three or four years is the usual recommended minimum for a crop rotation, but it can certainly be longer. If you know that your soil has a serious, persistent problem, such as potato cyst nematode, onion white rot, or clubroot, you may need a much longer rotation to grow susceptible crops with any success. 

Symptoms A common, serious problem in warm, wet seasons when it spreads rapidly. Less frequent in dry conditions. Potato dark blotches on leaves, mainly... 

The levels of antifeedants can be raised safely only in plants such as forest trees or fiber crops, not in food plants for humans or livestock. Such problems have arisen inadvertently. For instance, a new insect-resistant potato cultivarhad to be withdrawn from the market because it contained high levels of the carcinogens solanine and chaconine (Renwick etal, 1984). In another example, an insect-resistant celery had 10 times the usual concentration of the carcinogen 8-methoxypsoralen (and related psoralens), which caused dermatitis in produce handlers (Seligman etal, 1987). 

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