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Over 500 species of pests have evolved a resistance to a pesticide. [4] Other sources estimate the number to be around 1,000 species since 1945. [5] Although the evolution of pesticide resistance is usually discussed as a result of pesticide use, it is important to keep in mind that pest populations can also adapt to non-chemical methods of ...
A fairly well-defined reaction front can often be observed in thin sections; ahead of the front the concrete is normal, or near normal. Behind the reaction front, the composition and the microstructure of concrete are modified. These changes may vary in type or severity but commonly include: Extensive cracking; Expansion
Pesticide resistance is increasing. Farmers in the US lost 7% of their crops to pests in the 1940s; over the 1980s and 1990s, the loss was 13%, even though more pesticides were being used. [102] Over 500 species of pests have evolved a resistance to a pesticide. [105] Other sources estimate the number to be around 1,000 species since 1945. [106]
The Herbicide Resistance Action Committee (HRAC) classifies herbicides by their mode of action (MoA) to provide a uniform way for farmers and growers to identify the agents they use and better manage pesticide resistance around the world. [1] [2] It is run by CropLife International [3] in conjunction with the Weed Science Society of America ...
This occur when concrete is placed under hot conditions, e.g. in the summer and not sufficiently protected against evaporation. Cracks often develop above reinforcement bars because the contraction of concrete is locally restrained at this level and the still setting and weakly resistant concrete cannot freely shrink.
Pesticide induced resurgence, often shortened to resurgence in pest management contexts, can be described as a constraint of pesticide use, by which they fail to control pests such as insects and spider mites: instead ‘flaring up’ populations that may have been of minor importance.
The Insecticide Resistance Action Committee (IRAC) was formed in 1984 and works as a specialist technical group of the industry association CropLife to be able to provide a coordinated industry response to prevent or delay the development of insecticide resistance in insect, mite and nematode pests. IRAC strives to facilitate communication and ...
Acceptable pest levels—The emphasis is on control, not eradication. IPM holds that wiping out an entire pest population is often impossible, and the attempt can be expensive and unsafe. IPM programmes first work to establish acceptable pest levels, called action thresholds, and apply controls if those thresholds are crossed.