The variable oak leaf caterpillar, Heterocampa manteo (Dbldy.), has defoliated hardwoods in two North Dakota locations for 3 years (Fig. 1). This is the second consecutive year its damage has been monitored. Monitoring has been done cooperatively with William Brandvik, Associate
State Entomologist, North Dakota Department of Agriculture.
Six Montana areas in which permanent mountain pine beetle trend plots were established in 1979 were revisited in 1980. Results of the visit show infestation intensity decreased significantly in Centennial Valley, decreased slightly in the Madison River plot area, and increased almost threefold in the Murr Creek area. Beetle populations...
Fungi associated with cankers of Russian-olive seedlings at the Montana State Nursery, Missoula, were investigated. Phomopsis elaeagni was most often isolated from and fruiting on cankers. Other associated fungi were Phoma herbarum, P. eupyrena, P. chrysanthemicola, P. exigua, Alternaria alternate, Epicoccum nigrum, and Fusarium moniliforme. Because of its common occurrence...
A synthetic pheromone of the western pine shoot borer, Eucosma sonomana Kearfott, has been used
successfully as a 'mating disrupter in northern Idaho and western Montana since 1984. Infestation
levels in treated ponderosa pine plantations declined from an average of 28 percent infested in 1983
to 5.5 percent by 1986....
Dwarf mistletoe is a serious problem on the Flathead Indian Reservation. Since the early 197o's, a procedure called thinning-sanitation has been applied to lightly infested stands. Evaluation of this procedure indicated that average dwarf mistletoe infection levels now range from 7 to 50 percent in larch and Douglas-fir treated 10...
Methods used to establish permanent plots in precommercially thinned and unthinned stands to monitor root disease development are described. Plots were established in 22 Armillaria-infested stands in northern Idaho and western Montana. The proportion of trees dead and infected was significantly higher for planted than for natural regeneration at the...
This report includes information obtained in both 1983 and 1984. Beginning in 1983, only four of the original six permanent plot locations in the State would be revisited. The two in the southwestern part of the State--Centennial Valley and Madison River--were not visited because of reduced beetle populations and 111.1...