PCR is a technique used in molecular biology to amplify a single copy or a few copies of a piece of DNA across several orders of magnitude, generating thousands to millions of copies of a particular DNA sequence. It can be used to detect a wide variety of viruses in grapevines and detection of ASBVd in Avocados.

Phytophthora is a fungus-like eukaryotic microorganism which spreads through soil-borne spores or via root-to-root contact, dispersing through soil, water or airborne causing crown and root rot of herbaceous and woody plants, including fruit, nut, ornamental trees and shrubs, as well as selected vegetable crops.

Phytophthora grows through a plant’s root system into the larger roots until it reaches the root crown area. Although many roots may be infected, there will still be plenty of other functioning roots to support the plant so on the surface it looks healthy despite the substantial infection below.

Once the root crown is girdled, water and nutrients cannot reach the leaves and the upper portions of the plant begin to wilt and die back. When the plant parts die, the spores stay with the organic debris but may wash down into the soil or potting medium, surviving a long time after the plant tissue has decomposed.

Using New Zealand Blue Lupins which are particularly susceptible to Phytophthora and show infection quickly, Linnaeus tests for up to 50 of the most frequently occurring Phytophthora using baiting techniques in soil, media and water by floating or partially immersing baits (lupin seeds) in a water and growing media mixture. 

The incubation period is 5-10 days for testing soil, water and media. Results for leaf or root material are generally available within 24 hours.