A mixture oftrans-2-hexenal;n-tridecane (60:40, w/w), the natural combination present in the defensive secretion ofCoridius janus (Hemiptera; Pentatomidae) was shown by comparison with similar aldehyde mixtures having longer and shorter chainn-alkanes, to be the optimal combination as a fumigant and a repellent against three test insect species,Anoplolepis longipes, Sitotroga cerealella, andCulex quinquefasciatus. Toxic values obtained for the three insects, respectively: 1/LC50, 1.72, 4.54, and 6.66 ppm while repellencies were 63%, 50%, and 69%. This study revealed that amongt-2-hexenal:n-alkane combinations those with medium carbon chains,viz C-11 and C-12, also possessed high toxicities and repellencies comparable to that of the natural combination while those with shorter and longern-alkanes possessed lower activity. Toxicities and repellencies ofn-alkane series were only moderate to low showing highest toxic values forn-tridecane at 1/LC50, 0.39, 2.32, and 2.32 ppm and repellencies at 31%, 30%, and 32% for the three test insects, respectively. This series, nevertheless, showed similar variation, medium length chains, C-11, C-12, and C-13 showing comparatively higher activity than other alkanes of shorter and longer chains. This study also revealed that the fumigant property of both alkane and aldehyde are of equal importance while repellency is heavily dependent on the aldehyde.

4-Methyl-5-nonanol (ferrugineol), the more attractive component of the aggregation pheromone of Rhynchophorus ferrugineus F. (Coleoptera: Curculionidae) was synthesized by a Grianard reaction with -butylmagnesiumbromide and 2-methyl-1-pentanal. Oxidation of 2-methyl-lpentanol in pyridinium chlorochromate wasused toobtain 2-methyl-1-pentanal.The overall-yield of the synthesis from 2-methyl-1-pentanol was 6i%. At a release rate of 0.38 f 0.08 mg synthetic ferrugineol per day from capillaries suspended in bucket traps filled with soap water, significantly more weevils were caught compared to a control trap (0.23 + 0.04 weevils/trap/day vs 0.00 weevils/trap/day respectively) in the field. Significant differences were not observed between male and female trap catches using ferrugineol as a bait (0.12 * 0.02Itraplday and 0.11 f O.Ol/trap/day respectively). Ferrugineol remained attractive to weevils for a t least 60 d. The weevil response to the bait was observed only between 1800-2000 and 0600-0800 h. In a comparative field assay of synthetic ferrugineol with the coconut bark steam distillate, a known attractant for the red weevil, ferrugineol attracted signiticantly more weevils than the latter (0.25 k 0.12 weevils/trap/day vs 0.06 k 0.04 weevils/trap/day, p<0.05).

Defensive secretion produced by adult males and females ofLeptocorisa oratorius, Fabricius (Hemiptera: Coreidae) living on the host plant,Oriza sativa, was analyzed by a combined gas chromatography-mass spectroscopy technique. Both male and female secretions consisted of two major components: (E)-2-octenal andn-octyl acetate, 76% and 16% (w/w), respectively. The remaining 8% were trace compounds, some of which were identified as hexyl acetate, 3-octenal, 1-octanol, and (Z)-3-octenyl acetate. In a survey among 38 coreid defensive secretions, (E)-2-octenal andn-octyl acetate were found to occur rarely in addition to coreid-specific compounds, while their combination as primary constituents was found to be unique. Toxicity and repellency of this secretion were evaluated using two household pests,Anoplolepis longipes andSitotroga cerealella, as test insects, and lethal concentration (LC50) values of 0.24 ppm and 0.14 ppm, respectively, and repellencies of 63% and 58%, respectively, were obtained. Comparing the above values with those of a pentatomid bug,Coridius janus, evaluated under the same conditions, it was apparent that this secretion has potential as a repellent to enemies ofL. oratorius but not as a toxicant to attack them. Bioassay on the alarm activity of this secretion revealed that it elicits alarm responses, alerting and dispersing aggregated male and femaleL. oratorius: this is followed by "self-coating" activities. In addition, some unique behaviors were also noted among alarmedL. oratorius.

4-methyl-5-nonanol (ferrugineol), the major component of the aggregation pheromone of Rhynchophorus ferrugineus F. was evaluated as a lure for trapping of this pest in coconut plantations in Sri Lanka. Trap design, longevity of ferrugineol in field conditions, and the effect of trapping on damage incidence of R. ferrugineus were studied. N-pentanol, a known compound present in coconut stem volatiles was used in combination of ferrugineol in all tested traps. Trap designs tested were; an open plastic bucket, a funnel trap, and a modified metal trap. The open plastic bucket (5 L) baited with ferrugineol-pentanol, which was hung on coconut palm stem at 1.5 m, caught significantly more number of adult weevils than ferrugineolpentanol baited funnel and metal traps. An open plastic bucket trap was six times less expensive than the metal trap currently recommended by the Coconut Research Institute, Sri Lanka. Ferrugineol remained effective as a bait for 12 weeks under field conditions. High capture rates of adult R. ferrugineus were obtained in ferrugineol baited open bucket traps in plantations where the initial damage incidence was high. Monthly surveys of individual palms during pheromone trapping revealed that a sharp reduction of the number of coconut palms damaged by R. ferrugineus in 10-hectare experimental blocks. Continuous trapping of weevils with ferrugineol over a period of time significantly lowered the infestation of this pest.

Steam volatiles ol'freqj~ly cut hanana stem were analyzed lly comhined. gas c b r o m a t o~~a p l~y-electroai~l;enno~apl~ic detection (GC-EAD) ailtl comhined gas cl~i~c~matograplly-niass spect~.ometry (GC-MS) to iclentifi n-hexan.ol, n-hcxanal, n-pentanol and cis-3-hexc?nol as host attractants for the banana stem borer, Cldotl~oi~c~s loir,qicollis. .Idcnlities of t h e ahovc compounds were confirmed 1,y comparalivc studies with aulhcntics. Female weevils responded sligl~tly mo1.c (:EAG 1.41k !).()I) t1:han male weevils (EAG 1.04 f 0.03) to tho steam distillate. Synthel;ic eclu~.valents of the ahove aktractant,~, were sul?iect;ed to EAG assay and 11-hexan0l elicitcd the l~iglicst EAG lesponse (0.39 k 0.02 mV)'in Ihc antelma clt' tllis weevil. The other synthetic at.Lractants, 11-hexanal, n-pentanol and cis-3-hexello1 elicited EAG responses in t.ba fi~llowing order; 0.15 mV, 0.10 mV, 0.0t) niV. Aniix(;u~.c ofthe ahovc synL11etic attraclants (SAM) also elicited a poor EAG response (0.2 nlV) in. O.loii,gicolli,<. In lield ,xpcljments n-hexanol singly o]..,in comhiuation with the agglogation phcromone o.TO, lorrgicollls Cailcd tc.) attract any weevils into traps. The synthetic nttractanl; mnix(;lli~e (SAM) also was not field nt.tractive while it,s combination wit11 lhe aggregation pl1er1)nlone of 0. loitgicollis was attractive wit,h a maximum rrleail catch of' ().(Xi k 0.21 weevils ILrapIweek. Undei the same contlitions, Ilowcvc~; thepest's known atlraclant system, the aggregation phcromone + banana stem tissue haited trap, 11ad a maximum mean catch of 29.16 + 7.02 weevils1 traplweek.