Damage to Italian Crops caused by Cyst-forming Nematodes.

Investigations were undertaken in 1982-88 to estimate yield losses of carrot, sugarbeet, wheat, and potato caused by cyst-forming nematodes (Heterodera and Globodera species) in several provinces of Italy. Soil samples were collected at planting in 0.5-ha sampling areas distributed in each crop's major production area. Yield loss estimates were based on nematode population estimates and on curves derived earlier relating nematode densities with crop yields in Italy. Estimated yield loss values were based on the average prices reported for Italy in 1989. Heterodera carotae caused carrot yield losses in the Foggia (20%) and Venice (12%) provinces. Heterodera schachtii was common in our samples, but sugarbeet yield losses were highest in the province of L'Aquila (21%), followed by Ferrara (4.2%), Ravenna (3.3%), Modena (2.7%), and Rovigo (2.6%). Globodera rostochiensis and G. pallida were widespread in only a few of the major potato growing areas, but yield losses are remarkably high at Forli (17%) followed by Bari (9%), Catanzaro (6%), Foggia (3%), and Trento (3%). Heterodera avenae was common on wheat in the sampled provinces, but caused less than 1% yield reductions. Values of total estimated yield losses were 21.1 billion (Italian liras) for potato, 13.8 billion for sugarbeet, 3.2 billion for carrot, and 2.6 billion for wheat.