Response of some scolytids and their predators to ethanol and 4-allylanisole in pine forests of central Oregon.

Lindgren multiple funnel traps were set up in pine forests of central Oregon to determine the response of scolytid bark beetles to ethanol and 4-allylanisole (4AA). Traps were baited with two release rates of ethanol (4.5 or 41.4 mg/hr) and three release rates of 4AA (0, 0.6, or 4.3 mg/hr) in a 2 x 3 factorial design. All traps also released a 1:1 mixture of alpha- and beta-pinene at 11.4 mg/hr. Of 13,396 scolytids caught, Dendroctonus valens made up 60%, Hylurgops spp. 18.5%, Ips spp. 16%, Hylastes spp. 1.8%, Ganthotrichus retusus 0.9%, and bark beetle predators another 2.8%. Increasing the release rate of ethanol in the absence of 4AA increased the number of most scolytid species caught by 1.5-3.7 times, confirming its role as an attractant. Ips latidens, Temnochila chlorodia, and clerid predators were exceptions and did not show a response to higher ethanol release rates. Release of 4AA at the lowest rate inhibited attraction of most scolytids, with a significant reduction in G. retusus, Hylastes macer, and Hylurgops porosus when compared to traps without 4AA. A high release rate of 4AA further inhibited responses for most beetles compared to low 4AA. Seven species were significantly deterred by high 4AA, including the latter three, and Hylastes longicollis, Hylastes nigrinus, Hylurgops reticulatus, and Ips latidens. Exceptions include Hylurgops subcostulatus, which was significantly attracted to both low and high 4AA, and I. pini, which was attracted to low and high 4AA in combination with low ethanol, but unaffected by either release of 4AA with high ethanol. Dendroctonus valens was significantly attracted to low 4AA and unaffected by high 4AA. Predators appeared to be less inhibited by 4AA than most bark beetles. Although 4AA can deter the attraction of some secondary bark beetles to ethanol in combination with alpha- and beta-pinene, this inhibition could be weakened for certain species by increasing ethanol release rates. 4-Allylanisole may have some utility for managing the behavior of secondary bark beetles sensitive to this compound.

Seasonal and tissue variation in taxane concentrations of Taxus brevifolia.

Analysis of seven taxanes: taxol, baccatin III, 10-deacetyltaxol, 10-deacetylbaccatin III, 7-xylosyl-10-deacetyltaxol, cephalomannine and brevifoliol in extracts from bark and foliage of pacific yew (Taxus brevifolia) showed a gradient of decreasing concentration from stem base to branch tip. This decrease is attributed to the generally higher concentration of taxanes in the phloem tissue and the decrease in inner bark thickness from base to branch tip. Analysis of taxanes extracted from stem bark and needles sampled over a growing season showed that most taxane concentrations were significantly lower in the needles than in the bark. Typically, taxane concentrations in bark increased from May through August; whereas, in needles, concentrations changed little during that period. Two exceptions were baccatin III, which in the summer reached levels equivalent to bark, and brevifoliol which increased from March to August, reaching levels in needles nine times greater than bark.

Ethanol and ambrosia beetles in Douglas fir logs with and without branches.

November-felled Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) logs with and without branches were left lying on the forest floor through August. In May, as the logs were being colonized by ambrosia beetles,Trypodendron lineatum (Oliv.) andGnathotrichus retusus (LeConte), the ethanol, acetaldehyde, and water concentrations in the delimbed logs were significantly higher than in the branched logs. Since both log types received the same rainfall, lower water contents in branched logs was probably the result of absorbed water being transported through the branches via capillary movement and evaporation. Lower tissue water levels could have prevented the establishment and maintenance of anaerobic conditions, thus limiting the synthesis of acetaldehyde and ethanol in the branched logs. By late August, the beetle densities in delimbed logs were 9-16 times greater than in the branched logs. Log ethanol concentrations could be a key chemical factor affecting the ambrosia beetle attack densities. Acetaldehyde concentrations in the logs also may have affected the attack densities.

Effects of nitrogen and Douglas-fir allelochemicals on development of the gypsy moth,Lymantria dispar.

Two experiments were conducted to examine the influence of foliar nitrogen, terpenes, and phenolics of Douglas-fir on the development of gypsy moth larvae. In the first experiment, foliar concentrations of nitrogen and allelochemicals were manipulated by fertilizing 3-year-old potted seedlings with 0 or 200 ppm nitrogen. Concentrations of foliar nitrogen (0.33-2.38%) were negatively correlated with the phenolics (15.8-24.4 mg/g). Sixth-instar larvae previously reared on current-year Douglas-fir needles were allowed to feed on these seedlings. Pupal weights (312.8-995.6 mg) were positively correlated with levels of foliar nitrogen, negatively correlated with amounts of foliar phenolics, and uncorrelated with terpene concentrations. In the second experiment, terpene and phenolic extracts from Douglas-fir foliage were incorporated at natural levels into artificial diets with high and low levels of protein nitrogen. Neonate larvae grew faster and were larger on the high nitrogen control diet (4.1-4.5%), however, fourth instars performed better on the control diet with low nitrogen levels (2.5-2.7%). Foliar terpenes incorporated into diet had little effect on neonate fitness, but may induce subtle physiological changes in later instar larvae. Phenolics, alone or in combination with terpenes, excessively suppressed growth and survival, with no individuals living through the fourth instar, regardless of the nitrogen level. Incorporating foliar phenolic extracts into artificial diet caused unnatural levels of toxicity and failed to clarify the effects of Douglas-fir phenolics on gypsy moth fitness. Foliar nitrogen is a key factor influencing gypsy moth development on Douglas fir, but may be mitigated to some degree by phenolics.

White alder and Douglas-fir foliage quality and interegg-mass influences on larval development of gypsy moth,Lymantria dispar.

Individual families of gypsy moth collected from a single population exhibited different degrees of fitness when fed diets of white alder, a suitable broadleaf host, and Douglas-fir, an unsuitable conifer host. Members of families on diets of Douglas-fir had significantly lower survival, longer larval periods, lower pupal weights, and shorter pupal periods than members of the same families fed alder. Foliar nutritional quality, including nitrogen level and allelochemical composition (terpenes and phenols), was considered the key factor responsible for these differences. Growth parameters differed significantly for families within diet treatments, indicating that the genetic resources of a family did affect performance somewhat. The influence of a family's genetic resources on larval survival was most notable when larvae were under the greatest nutritional stress.

Influence of sagebrush terpenoids on mule deer preference.

The effect on mule deer (Odocoileus hemionus hemionus Rafinesque) preference of compounds in mountain big sagebrush [Artemisia tridentata Nutt. ssp.Vaseyana (Rydb.) Beetle], Wyoming big sagebrush (A. t. ssp.Wyomingensis Beetle and Young), basin big sagebrush (A. t. ssp.Tridentata), and black sagebrush (A. nova Nels.) was compared using a two-choice preference test. Compounds tested included:p-cymene, 1,8-cineole, methacrolein (two concentrations), and the nonvolatile crude terpenoid fraction (NVCTF) from each taxon. The compounds were tested by applying them to chopped alfalfa hay at concentrations similar to those found in nature. The intake of the treated hay was compared with that of an untreated control. Eight deer were used as test animals in an 8 - 8 Latin-square design. All compounds tested significantly deterred ingestion (P < 0.05). Compound influence on preference, in order of increasing deterrence, was as follows: 50% methacrolein, mountain big sagebrush NVCTF, methacrolein, basin big sagebrush NVCTF,p- cymene, Wyoming big sagebrush NVCTF, black sagebrush NVCTF, and 1,8-cineole. Methacrolein appears to be an important preference determinant among big sagebrush subspecies, andp-cymene between black sagebrush and big sagebrush. The NVCTFs containing sesquiterpene lactones as one of their constituents were closely related to the preference of all four taxa. Future studies of animal preference for sagebrush should consider all of the potential defensive chemicals in the foliage.

Phytotoxic properties of cnicin, a sesquiterpene lactone fromcentaurea maculosa (spotted knapweed).

Water and solvent extracts from the aerial tissues ofCentaurea maculosa, spotted knapweed, inhibited the root growth of lettuce. Column chromatography and lettuce bioassay of a chloroform extract led to the isolation of cnicin, a sesquiterpene lactone. Pure cnicin was bioassayed at 0, 1, 2, 4, 6, 8, and 10 mg/5 ml water with lettuce, created wheatgrass, bluebunch wheatgrass, rough fescue, western larch, lodgepole pine, and spotted knapweed. Germination was inhibited at one or more concentrations for all species except lodgepole pine and spotted knapweed. Growth, particularly of the roots, was retarded between 1 and 4 mg of cnicin. Lettuce, bluebunch wheatgrass, and spotted knapweed were inhibited significantly at all concentrations tested.

Enhancement of enzymatic hydrolysis by simultaneous attrition of cellulosic substrates.

It has been shown that simultaneous attrition of cellulose in an attritor containing stainlesssteel beads results in a substantial enhancement of the enzymatic hydrolysis. The attrition exerts two opposing effects, continuous delamination and comminution of the substrate with formation of new reactive sites and a gradual denaturation and inactivation of the enzyme. Consequently, the hydrolysis proceeds very rapidly at first and levels off at about 70% saccharification of the substrate. Accumulation of hydrolysis products is also responsible for inhibition of the enzyme. The attrition method is effective for the saccharification of cottonwood in which the cellulosic microfibrils are embedded in a matrix of lignin and hemicelluloses. A comparison between the saccharification of wood, lignocellulose, holocellulose, and cellulose with simultaneous attrition showed that the lignin component provided more hindrance toward the saccharification process than hemicelluloses, which are themselves subject to enzymatic hydrolysis.