Whitemarked tussock moth, Orgyia leucostigma, cocoons were monitored in a black walnut, Juglans nigra, plantation in Michigan from 1978 to 1981. Larvae spun cocoons on the exposed bark of the bole (29.6070), in crevices on the bole formed by pruning wounds (17.5%), beneath limbs (24.2%), and in branch crotches (28.7%). Parasites and predators destroyed 88% of the pupae in their cocoons. The tussock moth population, although moderate to high in the egg stage, decreased sufficiently in the larval stages each year to cause no more than 5010 defoliation to individual trees.

Contarinia baeri is univoltine in Michigan. Adults emerge in spring, and females deposit eggs in small clusters in the sheaths of new-growth pine needles. Larvae hatch shortly thereafter and there are three larval instars. Larval feeding causes the needles to at first droop, discolor, and eventually drop, reducing the quality of Christmas trees and occasionally killing shoots. Larvae overwinter on the ground in cocoons, and pupate in spring. Adults were suppressed (> 75% control) with formulations of Pydrin® (fenvalerate) and Tempo® (cyfluthrin) applied within a week after adult emergence.

A method is proposed for rapidly estimating the nymphal population of the Saratoga spittlebug on alternate host plants in young red pine plantations. The method is based on an assumption that the number of nymphs per sample unit is distributed within an infested plantation according to the negative binomial distribution. This method can be 1.1-11.0 times more efficient depending upon the density of plants and the nymphal population level.

Neolasioptera brevis is univoltine in Michigan. Adults issue in late spring, and females deposit eggs in rows on the lower side of young shoots of honeylocust. Larval eclosion occurs shortly after: there are three larval instars. The gall is polythalamous and may have 20 or more larvae. The third-instar larvae overwinter, and pupation occurs in spring. The gall injury kills sorne shoots, but most damage is cosmetic. One can monitor for adult emergence in late April or May by observing cast pupal cases protruding from the gall. Control, if needed, should be directed at adults.

Saperda inornata attacks on hybrid Populus were monitored in a stand for four years after planting. More than 60% of the whips were attacked the first year, resulting in a mean of 1.6 galls/tree (range 0-8). Branch attacks superseded stem attacks in the third and fourth years. Saperda injury significantly reduced height because of leader breakage after the second-year attacks, but the injured trees grew rapidly and recovered much of the height in the third and fourth years. Saperdas killed 4% of the trees during the study, but this was no more than would be expected in a newly established stand. Saperda, at the population levels studied, does not seem to greatly affect hybrid Populus growth or to reduce biomass.

Susceptibility ranking of more than 50 clones of hybrid Populus whips showed a wide range of attack ranging from none to very heavy. Clones with P. x jackii parentage were the most susceptible, whereas Carolina poplar was unscathed. Growth loss differed little between very heavily aphid-attacked whips and unattacked whips. Two insecticidal soaps adequately controlled the aphid but one caused some phytotoxicity to Populus.

Numbers of Malacosoma americanum caterpillar tents were positively correlated with average numbers and biomass of cherry trees as well as with amount of sludge applied. The enhancing effect of sewage sludge on amounts of black cherry biomass and foliar nitrogen may have been the principal factors leading to higher tent caterpillar populations on fertilized plots.

The tarnished plant bug injured 21 Populus clones in the clonal nursery of the Packaging Corporation of America in Michigan. Degree of injury ranged from 0.5 to 81.09<. Clone 'Wisconsin 5' sustained the heaviest attack, followed by Imperial Carolina poplar. 'Wisconsin 5' was salvaged by changing the standard and accepting shorter cutting stock for outplanting.

Adult pales weevils react to light and temperature cues regarding their movements in pine plantations. They remain at the base of their host trees during the day and move onto the trees after dark. A drop in light intensity to 2 fc triggers this response. Ambient temperature below 10°C curtails their movements. Weevils placed on the ground are photophobic at temperatures below 20°C and photophobic and thermophobic above 35°C. Orientation is erratic above 40°C and heat stupor occurs in a few minutes.

Eastern white pine and Scotch pine stumps with living branches were unattractive to pales weevil for breeding. When feasible, leaving a few lower branches on Christmas tree stumps during harvest should prevent weevil buildup.

A forest management team was organized in the late 1970's by cooperative efforts of Michigan's universities. the Michigan Department of Natural Resources, and the USDA Forest Service.The goals were to devise new technologies, transfer available technology, and service and management alternatives to forest land managers in Michigan. The program throughout has emphasized forest management rather than pest management for prevention and control of pests. Dissemination of pest management information has been of importance and new research results have gone directly to land managers for immediate use. The team participates in forest compartmental reviews and helps prescribe management plans for land parcels, thus providing for preventative pest management. Services and management recommendations are provided mostly through forest pest specialists located in the field. They feed back results and problems to researchers and extension specialists of the team for further input. Preventive management information used by by local managers in recent years has nearly paid the cost of the program. Plans are to broaden the team effort by cooperating with organizations and in adjacent states through a computer network system and by other means .

The ecology of the redheaded pine sawfly was studied relative to its impact on red pine plantations. An ecological model, which formed the basis for socioeconomic analysis, was constructed. Because the sawfly prefers trees under moisture stress, damage is most severe in stands growing on sand blows, where there is competition for moisture from bracken fern and hardwoods, and where soils are too moist, too shallow, or too compacted. Outbreaks also appear to be related to dry years. The sawfly has a variable impact on multiple-use values. Because it injures the least productive trees in a stand, timber is only indirectly affected. Small openings created by tree mortality after an outbreak may provide edge 'Wildlife habitat. The sawfly has both negative and positive effects on recreationists, depending upon the type of recreation; it may be a nuisance to campers, but may positively influence hunting. Preventive sawfly management involves proper site selection for red pine.

The tarnished plant bug, known principally as an agricultural pest, injures young hybrid Populus by feeding on the stems and meristems. Tarnished plant bug eggs, fungi associated with some lesions, and simple mechanical stimuli alone from feeding appeared not to cause lesion formation. Of 20 Populus hybrids tested in a clonal trial, four appeared to be consistently susceptible to lesion injury, with Populus nigra var. betulifolia x trichocarpa the most susceptible. Several clones showed high resistance in the trial but a few were susceptible in other plantings and in host preference tests when caged with tarnished plant bugs. Lesions diminished tenfold on Populus where horseweed, the insect's principal wild host, grew along with susceptible poplars. The tarnished plant bug can be suppressed by ultra-low volume pesticides and cultural manipulation of understory vegetation.

White grubs affect pine plantations by killing some trees and by reducing vigor and growth of others. Light to moderate mortality only slightly affects timber yields and financial re- turns if the level of trees remains at the number required for full utilization of the site. Reduced height growth, however, lowers apparent site quality and substantially affects yields and financial returns. The 100 year projections suggest that greater product volumes, financial returns. and higher interest rates on the investment will be gained by grub control before tree growth is reduced.

The butternut curculio, Conotrachelus juglandis LeConte (Coleoptera: Curculionidae), injures the shoots and nuts of various species and hybrids of Juglans in eastern North America. This insect was described in 1876 (LeConte, 1876); its life history has been studied in Connecticut (Britton and Kirk, 1912) and in West Virginia (Brooks, 1922). Its range, however, extends from the New England states through southern Canada to the Great Plains and south to Kansas, Alabama, and Georgia, contiguous with the natural range of butternut (J. cinerea), its native host.

(excerpt) The butternut curculio, Conotrachelus juglandis LeConte (Coleoptera: Curculionidae), injures the shoots and nuts of various species and hybrids of Juglans in eastern North America This insect was described in 1876 (LeConte, 1876); its life history has been studied in Connecticut (Britton and Kirk, 1912) and in West Virginia (Brooks, 1922). Its range, however, extends from the New England states through southern Canada to the Great Plains and south to Kansas, Alabama, and Georgia, contiguous with the natural range of butternut (J. cinema), its native host.

Pine root tip weevil, Hylobius rhizophagus, and pine root collar weevil, H. radicis, attack certain Scotch pine stands simultaneously causing more mortality than expected from either insect alone. Recommendations for curtailing this insect complex include favoring red pine, planting Scotch pine far from brood sources, and avoiding stump culture of Christmas trees.