Symptoms of foliar nematodes on chrysanthemum. Foliar nematodes have relatively short life cycles going from egg to adult in approximately 2 weeks. Females can produce large numbers of eggs, so symptoms can occur and spread fairly rapidly. For a literature review, cf. Bik et al. (2009): Small worms big ideas: evolutionary inferences from nematode DNA. Journal of Biogeography, 37(1):2009. doi: 10.1111/j.1365-2699.2009.02219.x