Plant protection weed control

Elmore CL (1991a) Cost of soil solarization. In DeVay JE, Stapleton JJ, Elmore CL (eds) Soil solarization. FAO Plant Production and Protection Paper 109, Rome, Italy, pp 351-360 Elmore CL (1991b) Weed control by solarization. In Katan J, DeVay JE (eds) Soil solarization. CRC, Boca Raton, FL, USA, pp 61-72... 

These days, allelopathic plants as catch crops or trap crops found utilization in plant protection of tropical regions against parasitic weeds. They do not eliminate the parasite completely but decrease the seed bank in the soil. Other applications of allelopathy for weed control include the use of plant residues as a natural herbicide agent, e.g., water extracts, pellets, flours, by-products of crop processing, etc. The strategies for use of volatile compounds as soil fumigants are developed. 

Allelopathic compounds act as repellents for herbivorous pests, so the same strategy used in weed control could be effective against pests and pathogens. Only allelopathy is not possible to use the complete control of weeds, pests or diseases it is necessary to combine it with other methods of plant protection. 

It is obvious that synthetic pesticides are important in controlling weeds and plant-pathogenic fungi, but in judging the efficacy of a method, it is essential to assess its nontarget toxicity, including health and environmental hazards. The literature abounds with reports that synthetic pesticides affect nontarget plants, their consumers and the environment (2). Thus, plant protection needs... 

There are more than 100 patents for plant protection by 1,2,4-oxadiazoles. For instance, the oxime ether (257) is claimed to be more effective than known compounds against Phytophthora infestans when applied protectively to tomatoes <87GEP(0)3528753>. Sprays of 5-trifluoromethyl-1,2,4-oxadiazoles, such as (258), show 90-100% protection against Erysiphe gmminis in barley <89JAP(K)63162680>. Other oxadiazoles, for example (259), show complete control of diverse weeds with no damage to rice crops <91JAP(K)02250873>. 

True yield potentials can only be expressed when the control of weeds, pathogenic agents, and insect pests are coupled with proper cultivation, fertility, and other plant protection measures. An example of these high yields in Western Europe appears in Table II (1). 

Controlled release of agrochemicals (e.g., by hydrolysis of a polymeric ester) can offer the advantages of constant level, smaller dose, reduced evaporation loss, lower toxicity, longer life, decreased environmental pollution, and reduced effect on nontarget species by wind or runoff.20 Systemic pesticides are preferred. This ensures protection of the growing tip of the plant. For weed killers, this means that it is not necessary to hit every leaf of the plant with the herbicide. Pesticides are often applied on a spray schedule according to the calendar as a prophylactic measure. Chemical pesticides are used 98% of the time. 

Ecosystem diversity and wildlife habitat indicators all indicate a favourable position for organic agriculture. The need for non-chemical plant protection, more extensive grazing regimes for farm animals, longer crop rotation cycles, management practices to shelter and stimulate wildlife diversity to contribute to natural weed and insect control, and others, all stimulate the presence of wildlife. 

Herbicide safeners (also referred to as herbicide antidotes or protectants) fulfill an important role in crop protection. Safeners are chemicals that protect crop plants from unacceptable injury caused by herbicides. Either by placement on the crop seed or by way of a physiological selectivity mechanism, safeners in commercial use do not negatively impact the weed control of the herbicide. Although many herbicides have been developed for use without a safener, some of the strongest and most broad-spectrum herbicides tend towards border-line crop selectivity, which may completely preclude use in a particular crop or at least limit maximum use rates or the crop varieties that can be safely treated. It is for such situations that safeners have been developed. Several books and reviews of safeners have been written over the past 20 years [1-3]. It is not the intention of this chapter to cover in detail older safeners, but rather to focus on more recently developed commercial safeners as well as some of the older compounds still in wide commercial usage. 

Amicarbazone is a new herbicide for broad spectrum weed control in com and sugarcane. It belongs to the chemical class of carbamoyl triazolinones and acts as an inhibitor of photosystem II. It was discovered 1988 by the former Plant Protection Division of Bayer AG (now Bayer Crop Science) and developed under the internal code no. BAY MKH 3586 (Pig. 10.3). 

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