Any organism in which the individual spends a major part of its life cycle inhabiting, and obtaining nutrients from, a single host individual. The term may be applied to a species , a population, or an individual. Plant parasites include insects, mites, nematodes, Angiosperms, fungi, bacteria, phytoplasmas, viruses, and viroids. Parasite gradients

The distribution of a parasite within a crop is usually uneven, with a gradual variation from a high density to a low density. This variation is known as a parasite gradient. Unless it is taken into account during recurrent mass selection , it can cause serious errors in the assessing of the level of horizontal resistance in individual selections. This problem can be overcome by the use of grid screening. See also: Patchy distribution. Parasite identification See: CABI.

Growing Soilless

Growing Soilless

This is an easy-to-follow, step-by-step guide to growing organic, healthy vegetable, herbs and house plants without soil. Clearly illustrated with black and white line drawings, the book covers every aspect of home hydroponic gardening.

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