Weeds definition

Pyrithiobac-sodium is a pre- and post-emergence herbicide to control broad-leaved weed and grasses The residue definition is for the parent, pyrithiobac-sodium, only. 

Stable to acid and base in the pH range 3-8. Thenylchlor is a chloroacetamide herbicide for the preemergence and post-planting control of annual grass and broad-leaved weeds in paddy rice The residue definition is for the parent, thenylchlor, only... 

The term allelopathy, when first proposed by Molisch (1 ), referred to either the beneficial or detrimental interaction between all types of plants and microorganisms. As presently used, this definition is generally accepted. Since 1970 a concerted effort has been made to understand the phenomenon of allelopathic interaction. The many interpretations resulting from these studies are well documented in the literature (2-4). An area currently receiving considerable attention is the allelopathic effect resulting from weed-crop and weed-weed interactions (2, 5-7). One study conducted by Wilson and Rice (7) showed that the common sunflower, Helianthus annuus L., possessed allelopathic properties. Realizing the inherent potential... 

This comprehensive definition makes it elear that a wide number of substances may be eonsidered to be pestieides, and that the eommonality among all pestieides is their ability to provide eontrol over pests. A variety of classifications for pesticides have been developed that are specific for the type of pest controlled. Insecticides, for example, are pesticides that control insects, while herbicides control weeds and fungicides control plant diseases (molds). In addition to these major classifications of pesticides, there are many other classifications. These include nematicides (for nematode control), acaracides (mite control), rodenticides (rodent control), molluscicide (snail and slug control), algacides (algal control), bacteriocides (bacterial control), and defoliants (leaf control). 

These symptoms characterize the critical phase of water supply and indicate that the tree definitely needs to be watered. Young trees and newly planted trees are particularly sensitive to drought and need to be watered in critical phases. In order to reduce drought stress, it is also very important to keep the planting area weed-free and/or cover it with various organic materials, such as manure. Care should be taken to... 

On musty organic odors and tastes of natural origin, as from leaves and weeds, ozonation has not proved entirely effective, though it has definite effects. In 8 months of 1951 and 1952 raw water characteristics were very similar. With ozonation functioning in 1951 only 20% of the plant effluent samples were determined as having musty odors, while in 1952 without ozonation, in spite of other treatments used, musty odors were present in 28% of the samples. 

A computer survey of the patent literature made a year ago came up with 515 recent patents claiming herbicidal synergies. A perusal of the abstracts of 45 of them, chosen as a sample, showed that the patent community uses a broader definition of synergy than used here they believe that there is a synergism when two herbicides control more weed species than each separately. This would better be termed "complementarity. The overlap of control range allows a lowering of herbicidal rates, which may or may not be due to a metabolic... 

With the first invasion of resistant weed populations, prompt action has been essential to avoid serious and permanent problems. Preventive action to avoid herbicide resistant weeds from evolving in the first place is definitely the best strategy. It is virtually essential in all cases of herbicide resistance to have other classes or types of herbicides, with alternate sites, modes of action and degradation available. In some countries, because of failure to respond promptly, the lack of suitable alternatives, or for other reasons, triazine resistant weeds have not been controlled, resulting in rapid spread,.leading to the almost total loss of effective weed control with these herbicides (1). 

Fertility stress from reduced fertilization and dense populations of plants contributes to aflatoxin development in preharvest corn (26). A definite relationship between increased aflatoxin levels in kernels from plants grown under nitrogen stress has been reported (45). The competition of weeds for available nutrients and water also has been linked to presence of aflatoxin in corn (46). 

Synonyms Angola weed Roccella fuciformis Definition Derived from Rocceiia fuciformis Uses Natural flavoring agent in alcoholic beverages... 

Definition Extract of the herb of the groundsel, Senecio vulgaris, a common weed in the daisy family... 

In this vision, the definition of vegetation has to be the whole of the plants of a landscape element, considered in their aggregation cap>acities and in their relations with environmental and time-space factors. Thus, a cultivated tessera is to be considered as vegetation not only for its weeds (e.g. Secalinetea, Chenopodietea), but even for the cultivation itself (e.g. Triticum aestivum, Hordeum vulgare), without which the weeds does not succeed and the tessera does not become the habitat for many natural species (e.g. Cotumix coturnix, Alauda arvensis), besides to be a crucial ecological component for human population. 

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