Patent ID: 7585641

Claim:
A method for detecting the presence of an infection in a plant caused by a virus selected from the group consisting of potyviridae and tobamoviridae, which comprises: (a) providing a detection apparatus which includes mounted on a support member an elongated membrane having a first end and a second end wherein in lateral contact with the first end of the membrane is a sample pad for receiving a liquid sample and in lateral contact with the second end of the membrane is a wicking pad which allows the liquid sample to flow through the membrane from the sample pad to the wicking pad and wherein the membrane further comprises at least one detection zone laterally spaced from the sample pad in which is immobilized an antibody which is specific for a protein of the virus end a reference zone laterally spaced between the detection zone and the wicking pad in which is immobilized a control antibody; (b) mixing a material from the plant with an extraction solution for a time sufficient to produce a mixture including the protein of the virus; (c) mixing an aliquot of the mixture from step (b) with naked, unmodified, visible polystyrene latex particles which bind to the protein of the virus at room temperature for a time sufficient to bind a sufficient amount the protein of the virus to the particles to enable visualization of the particles bound to the protein and without substantial binding of other components of the mixture to the particles; (d) mixing a particle blocking solution including a blocking agent with the mixture in step (c) at room temperature for a time sufficient to block sites on the particles not bound to the proteins of the virus; and (e) applying the mixture from step (d) to the sample pad in the detection apparatus at room temperature wherein binding of (i) the protein of the virus bound to the particles by (ii) the antibody specific for the protein of the virus that is immobilized in the detection zone indicates the presence of the infection.