Distribution, Biology and Pathology of <I>Anguina pacificae</I>

Abstract

Anguina pacificae is distributed along a narrow strip on the Pacific coast of Northern California where it forms galls on the shoots of Poa annua and causes significant damage to golf course greens. Methods were developed for the continuous propagation of A. pacificae on P. annua in growth chambers, and they were used to examine the life cycle and host-parasite relationships of the nematode. At a mean temperature of 208C (228C day/188C night) the life cycle was completed in as little as 32 days (inoculation to second-generation J2). The first molt occurred in the egg. Infective J2 hatched from the eggs and penetrated the shoot near the crown of the plant where a cavity was formed 200 to 300 mm below the shoot apex. A gall around the cavity was visible 12 days after inoculation (DAI), and the cavity and gall continued to enlarge until second-generation J2 began to hatch. Three additional molts occurred in the cavity of the developing gall 14 to 24 DAI. Sexes could be distinguished 15 DAI. Egg production began 26 DAI and continued for 10 to 15 days. Eggs commenced hatching inside the gall 42 DAI, when the adults began to die and decompose. By 57 DAI, the gall had reached its maximum diameter, and the cavity was filled entirely with second-generation J2 that remained in the gall until they were liberated when the gall decomposed. J2 in galls survived desiccation over silica gel for 14 months at 148C and were active and infective when rehydrated.