COMPOSITION FOR ATTRACTION OF PINE SHOOT BEETLES

Abstract: Composition for attracting pine shoot beetles (Tomicus piniperda) containing terpene hydrocarbons from pine resin. The composition also contains ethanol, with the exception of a composition only containing alpha -pinene and ethanol.

Description: COMPOSITION FOR ATTRACTION OF PINE SHOOT BEETLES The pine shoot beetle is a bark beetle species which undoubtedl belongs to the most serious pest insects on pine in large parts of the world. The flight times for pine shoot beetles is early in the spring. The beetles in flight attack fresh pine logs. Some times they also attack living pine trees. For both specie the female first bores itself into the bark and starts to make breeding galleries in the bast layer. The flight of the beetles is strongly weather dependent. It starts when the temperature exceeds 11 to 12°C. All according to yearly and geographic variations this takes place in the time interval from early Apr until late June on the nothern hemisphere. Normally the flight is over in a matter of few weeks, and very little is known abou later flight acitivity. It has been assumed that the olfactory attraction of the pine shoot beetle Tomicus piniperda to the host tree is caused the monoterpene hydrocarbones, such as terpinolene and α-pinene, which are contained in the liquid resin in Pinus sylvestris. Host selection and colonization for reproduction occurs at time and according to a pattern which is not congruent with a pheromone governed mass aggregation observed in bark beetles colonizing host trees in response to insect born attractants (Vite, J.P., Francke, . : Chemie in uns. Zeit 19, 11 (1985)), a also not in conformity with the chain of events in the host selection process observed in insects visiting unimpaired host plants. Instead, massive flights occur early every spring, leading to an instant and simultaneous colonization of suitable breeding material, apparently unrelated to previous successful beetle attacks. The investigations conducted so far neither prove (Schδnherr, J. : Z.ang.Ent. 71, 410 (1972)) nor imply (Langstrδm, B., et al.: Z.ang.Ent. 99, 174 (1985)) the existenc of pheromonal components in T. piniperda aggregation, while the obvious attractivity of uninfested pine bolts to a beetle population in flight suggests that host recognition is primaril correlated to host odours, presumably constituents in liquid pi resin. After a further consideration we found that the resinous odours emanating from trees, slash and the like can hardly be t reason for the Ins antaneous colonization of stumps and logs, unless the host specific terpenes are complemented by other substances which healthy pine trees lack. In the numerous studies carried out during the last 30 years with respect to the choice of host made by T. piniperda (Oksanen, H., et al.: Contrib. Boyce Thompson Inst. 24, 299 (1970)) one has not taking into consideration a mechanism which is characteristic to the olfactory orientation of certain non-agressive bark beetles which for their reproduction depend on a highly suitable hos material. When trees are deceased or weakened, or in stumps and logs, an anaerobic fermentation takes place leading to the formation of ethanol (Granha , K. , Ca.J.Zool, 46, 905 (1968)). We found that it was possible that this ethanol was the reason why the pine shoot beetle attacks a host tree. In order to test this hypothesis under field conditions cone traps (Rόchling-Flachtrichterfallen) were placed 8 m apart in pine forests containing endemic populations of T. piniperda. The » traps were baited alternately with a mixture of terpinolene and racemic α-pinene in a ratio of 1:1, and a mixture of terpinolene, α-pinene and ethanol in a ratio of 1:1:3, and these mixtures were released from 3x5 cm porous pads enclosed in a polyethylene dispenser bag. (0.05 mm low density PE) . The number of beetles (x) caught per treatment were transformed with the formula Vx+0.5 (Oksanen, see above) and subjected to an analysis of variance. Significant differences among treatment means were identified at the 0.05 probability level using Duncan's multiple range test (Roelofs, W.U. , Cardέ, R.T. : Ann.Rev.Ξntomol. 22, 377 (1977)) . The results obtained, illustrated in the table below, fully support the hypothesis that the phenomenon with instantaneous colonization of pine stumps and logs, particularly of T. piniperda female beetles, is at least partly due to a ' synergistic effect between primarily (monoterpenes) and secondarily (ethanol) formed host odours emanating from pine host trees with reduced growth. It is possible that sex-related pheromones have an influence on the ratio between male and female beetles caught. Table The catch of T. piniperda in cone traps containing terpinolene and α-pinene (A) or A and ethanol (B) . In each case 12 tests were made at three different locations in the forest. Bait Average number Total number per trap/day Control 1 0.3 4 A 2 0.8 10 B 3 10.9 131 A 2.6 31 B 22.3 267 A 0.9 11 B 13.3 160 A 0.9 11 B 13.4 . 161 A - 1.3 16 B 9.1 109 1 Traps without bait 2 PE bag with porous sheet (4x5 cm) and 3 ml terpinolene and α-pinene (1:1) 3 PE bag with porous sheet (4x5 cm) and 5 ml terpinolene, α-pinene and ethanol (1:1:3) . The ratio between the components in the bait may be varied, but it is essential that the desired attractants are present as long as possible in order to obtain the longest possible duration of the effect. In addition to terpinolene and α-pinene other terpenes occuring in pine may be used either instead of or in addition to terpinolene and α-pinene. Examples of such other substances are pine resin, β-pinene, myrcene and 3-carene. Racemic and optically active forms may be used. From Naturwissenschaften 62 (1975) p. 539 it is known that a mixture of α-pinene and ethanol has a certain attraction on Trvpodendron lineaturn, but from ibid 66 (1979) p. 528-529 it is seen that the same mixture has practically no attractive effect on the same beetle. In view of the fact that the response to a certain chemical mixture is known to be specific for each species, there was no reason to believe that a mixture of α- pinene and ethanol should have any effect on other insects, in particular Tomicus piniperda.

Claims: 5 P a t e n t C l a i m s : 1. Composition for attracting pine. shoot beetles (Tomicus piniperda) containing terpene hydrocarbons from pine resin, c h a r a c t e r i z e d i n that it also contains ethanol, with the exception of a composition only containing α-pinene and ethanol. 2. Composition according to claim 1, c h a r a c t e r i z e d i n that it contains terpinolene and ethanol. 3. Composition according to claim 1, c h a r a c t e r i z e d i n that it contains terpinolene, α-pinene and ethanol.

Inventors: BAKKE ALF, VITE JEAN PIERRE, BAKKE, ALF, VITE, JEAN, PIERRE
Applicants: BORREGAARD IND, BORREGAARD INDUSTRIES LIMITED
Application year: 1986
Main classification: A01N31
IPC codes: A01N31