Fusiform Rust Infection of Loblolly and Slash Pines After Artificial Inoculation and Natural Exposure in Plantations
Seedlings from progenies of slash and loblolly pines were divided into two groups. One group was exposed to the fusiform rust fungus in greenhouse inoculations by the concentrated basidiospore spray system and the other was exposed to natural infection in field progeny tests. Within families, correlations between percentages of seedlings infected after field and artificial exposure were 0.6 to 0.8 for three slash pine plantations and 0.4 to 0.6 for six loblolly pine plantations. Most progenies were highly susceptible to infection, particularly under artificial conditions. Greenhouse inoculations usually identified highly resistant progenies but not those with small amounts of resistance.