Research Topics Insects and Disease
Insects and Disease
The pitch canker fugus, Fusarium circinatum (= F. subglutinans f sp. pini), causes several serious diseases of pines. The pathogen infects a variety of vegetative and reproductive pine structures at different stages of maturity and produces a diversity of symptoms.
In addition to producing resinous cankers on the woody vegetative structures of its pine host, the causal fungus causes the mortality of female flowers and mature cones, deteriorates seeds of several pine species, and can cause mortality of seedlings in nurseries. Since 1986, pitch canker has been epidemic in California on Pinus radiata (Monterey pine) and has all the earmarks of an introduced disease. 1
Scientists have investigated Pitch Canker (Fusarium circinatum) on Douglas-fir in the Sierra Nevada using a disease resistance approach. The pathogen was recently detected in New Zealand via PCR testing on a shipment of scion. An evaluation served as the basis for an eradication project in a USDA-FS seed orchard. The Institute of Forest Genetics is also collaborating with Australia, New Zealand and other countries to evaluate resistance of Monterey pine stock to Fusarium circinatum.
The "Beetle in a Haystack" project (joint venture with California State Parks, UC Davis, UC Berkeley, and USDA Forest Service:
Pine pitch canker is a source of high levels of mortality among native Monterey pine stands in coastal California. There is some evidence that it is now in Sierran Douglas-fir trees, but workers have had trouble isolating it from needles because the disease has fewer overt symptoms in Douglas-fir.
The current approach to delimiting pine pitch canker in the Sierra Nevada is to walk around doing "leaf wipes" which are then cultured for the fungus. This project is intended to develop pheromones to trap beetles (which carry spores of Fusarium) as a surrogate for leaf wipes. It's much more efficient because the pheromones draw beetles from long distances, so we can save a lot of footwork by harnessing that beetle-power.
Once we trap the beetles, we can culture them en masse for spores, if there is even one beetle in 400 carrying spores, we'll get a positive culture (hence the nickname "beetle in a haystack").
1Dwinell, L. David. 1999. Contamination of Pinus radiata Seeds in California by Fusarium circinatum.