This principle aims at eliminating a pathogen after it is introduced into an area but before it has become well established or widely spread. It can be applied to.

________involves the practices directed to exclude, reduce or

eradicate inocula.

_________is a viral disease transmitted by

aphids, and it causes dark lines on the leaf

veins (mottling), leaf discoloration, distortion,

dwarfing and in lettuce, failed to produce a

marketable lettuce head.

Considered to be one of the major constituents of the agro-ecosystems.

Most weeds have a short life span if not similar to the crop with which they compete.

Dormancy is the inability of the seed or any vegetative organ or tissue to germinate under favorable conditions.

There are two types of dormancy, the innate dormancy and the ________

The principles of weed control include the following: prevention, eradication, control, and ___________________

Herbicide which tends to move from treated parts to untreated areas through xylem/phloem depending on the nature of its molecule.

Some problems associated with herbicide use are the residues in soil and crops.

No single method is successful under all weed situations. Many a time, a combination of these methods gives more effective and economic control than a single method.

Butachlor is what type of chemical formulation?