Chafer beetles

The complete replacement of chlorine in the DDT molecule by fluorine gives (p-FCeH CHCFs, a compound with greatly decreased toxicity toward fruit flies and thrips and probably other species. This reduced activity is matched by the low activity of (p-ClCeH CHCFs which, when contrasted to the potency of DDT and DFDT, shows that the attenuation is caused by the replacement of the three chlorine atoms on the alkane bridge. The corresponding substitution of only one chlorine atom by fluorine gave a compound having as much activity as DDT against the chafer beetle. 

In contrast to the rutelines, the melolonthine scarabs generally use terpenoid-and amino acid-derived pheromones (reviewed in Leal, 1999). For example, the female large black chafer, Holotrichia parallela Motschulsky, produces methyl (2.S, 3. Sj - 2 - am ino-3-methy lpcn tanoatc (L-isoleucine methyl ester) as an amino acid-derived sex pheromone (Leal et al., 1992 Leal, 1997). There is no direct evidence that the chafer beetles or any other Coleoptera use the shikimic acid pathway for de novo pheromone biosynthesis, but some scarabs and scolytids (see section 6.6.4.2) may convert amino acids such as tyrosine, phenylalanine, or tryptophan to aromatic pheromone components (Leal, 1997,1999). In another melolonthine species, the female grass grab beetle, Costelytra zealandica (White), the phenol sex pheromone is produced by symbiotic bacteria (Henzell and Lowe, 1970 Hoyt et al. 1971). 

Although not of fatty acid origin another group of scarab beetles utilizes amino acid derivatives as pheromones [119]. The large black chafer, Holotrichia parallela, uses L-isoleucine methyl ester [ 120] and the cranberry white grub, Phyllophaga anxia, uses both L-isoleucine and i.-valine methyl esters [121]. More recently L-isoleucine methyl ester, N-formyl L-isoleucine methyl ester, and N-acetyl L-isoleucine methyl ester were identified in the scarab beetle Phyllophaga elenans [ 122]. These pheromone components are obviously derived from the amino acids isoleucine and valine. 

Scarabaeidae (Scarab Beetles, Chafers, Dung Beetles). 109... 

Pheromone chemistry in scarab beetles, chafers, and dung beetles covers a wide range of structures, including esters of amino acids and aromatics as well as branched and straight chain aliphatic compounds, among which a row of y-lactones forms a most characteristic group. 

Extracts of the summer chafer, Amphimallon solstitiale L. (Coleoptera Scarabaeidae), a common European scarab beetle were analyzed by GC-MS and GC-EAD. Both male and female extracts were shown to contain Acetoin — R) (5) > 9 1, as well as 2,3-butanediol — 2R, 3R) (25,35) meso =1 1 9. Although (25, 35)-butanediol did not show any activity, the other compounds elicited strong responses exclusively with male antennae. 

Everard Britton is one of Australia s most distinguished entomologists. For more than twenty years, he was a curator at the Natural History Museum in London. Now he s retired but still retains his passion for beetles such as chafers and the Melolonthinae. 

Insects provide another difficulty. One of the axioms of entomology is that in the Northern Hemisphere, insect populations are larger and more varied in the eastern parts of a continental mass. In addition to its other problems, eastern viticulture must do constant battle against numerous voracious insect pests. The rose chafer regularly appears just in time to nip off inflorescences as they are about to flower. The Japanese beetle turns every leaf of a grapevine into a piece of lace, if allowed to. In the Tidewater sections of the lower part, nematode infestation can be so severe as to make viticulture almost impossible. 

Figure 10.6 Relationship between generations per year and development of resistance in species selected by soil application of aldrin/dieldrin. 1 and II, root maggots III, southern potato wireworm IV, northern corn rootworm V, European chafer VI, Japanese beetle VII, sugarcane wireworm. (From Georghiou, G.P. and Taylor, C.E., in Pesticide Resistance Strategies ami Tactics for Management, National Academy Press, Washington, D.C., 1986,157 With permission.)...

At Geneva, N. Y., several hundred compounds have been tested as candidate attractants for the European chafer [Amphimallon majalis (Raz.)], a serious pest of turf. The best compound was butyl sorbate this was produced commercially and used for the first time in 1962. Although it is not much superior to the Java citronella oil-eugenol standard bait previously used (96)/it has the advantage that it does not attract the Japanese beetle. With the old bait, Japanese beetles clogged the traps. Homologs of butyl sorbate are active. 

Leaves skeletonized. Cause Leaf-feeding beetles. Japanese beetles are prime suspects here, although other beetles, such as spotted cucumber beetles and rose chafers, may also attack. Handpick or spray with a solution of 1 tablespoon 70 percent isopropyl alcohol to 1 pint prepared pyrethrin mixture. Repeat every 3-5 days until beetles are gone. 

Leaves and flowers skeletonized. Cause Rose chafers. This /s", reddish brown beetle with thick, yellowish hairs on its wing covers appears in late spring and damages both leaves... 

The Coleoptera (beetles) contains about 300,000 species and are very varied in form, diet and habitat. Equally they have very different kinds of pheromones and defensive secretions, many of them derived from fatty acids. The bean weevil Acanthoscelides obtectus uses an unusual allenic methyl ester (Figure 3.25). Its biosynthesis has not yet been investigated. Allenes are an unusual example of chirality. Anomala cuprea, a chafer grub produces two lactone sex attractants, derived from the unsaturated acids oleic and palmitoleic acids (Figure 3.25). Both are shortened by the loss of two acetic acid units, then oxidized (stereospecifically) at the allylic position and cyclized to the pheromone. 

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