Introduction. In the water-savingand income-generating agroforestry cropping systems developed andpromoted by the ICRISAT in the Sudano-Sahelian zone of West Africa, particularlyin Niger, fruits of domesticated Ziziphus mauritiana (“applesof the Sahel”) are severely damaged by fruit flies (Carpomya incompleta),and chemical pesticide application poses economic, environmentaland human health problems. In the Bio-reclamation of Degraded Lands (BDL)system, apple of the Sahel is the main high-value crop, while inthe Dryland Eco-Farm (DEF), it is grown alongside watermelon. Sclerocaryabirrea (marula plum) is presently being investigated asa dryland tree species for fruit and oil production, either in orchardsor such systems as BDL. Materials and methods. To completepreliminary results of earlier studies published elsewhere, we collectedand incubated in 2010 ripe fruits of marula plum and watermelonin Sadoré, Niger, where the above-mentioned agroforestry systemsare developed, and we recorded emerging fruit flies. We also conducteda spot-spraying experiment (using GF-120) in an apple of the Sahel orchardin Niamey in 2010; we recorded undamaged and damaged fruits and incubatedthe latter. In the same orchard, we set up in 2011 a fruit fly trappingsurvey targeting the invasive species Bactrocera invadens (Chempac®traps using methyl eugenol as the attractant). Results and discussion.The results showed that only Ceratitis cosyra emergedfrom marula plums, and only Dacus spp. from watermelon.The GF-120 spot-spraying experiment showed that C. incompleta was notattracted / intoxicated, contrary to Ceratitis spp.and Dacus spp.; the sprayed trees yielded significantly moremarketable fruits than unsprayed ones; only C. incompleta emergedfrom damaged fruit. Detection trapping revealed for the first timethe presence of B. invadens in the Sahelian zone ofNiger, including at the time of apple of the Sahel fruit production. Conclusion. This, alongside results of earlier studies,suggests a repellent effect of GF-120 on the monophagous C. incompleta species(Trypetinae), while it is attractive to oligophagous/polyphagousDacinae fruit flies; some of them (e.g., Dacus spp.)damage watermelon, which is part of the DEF system, and producefruit at the same time as the jujube tree. The prospects for harnessingthese two opposite regulation pathways are discussed.

Introduction. Fruit flies contribute significantly to yield losses experienced by citrus farmers in Nigeria. The majority of farmers have meager resources and limited knowledge of appropriate citrus pest management strategies. The best alternative for them is the application of control methods that are environmentally friendly and affordable. Our work was therefore designed to develop baits from a cheap source for monitoring fruit fly populations and controlling them while minimizing environmental hazards. Materials and methods. Protein bait prepared locally from brewery yeast waste by the process of heat autolysis was compared with the imported protein hydrolysate bait in McPhail traps. These traps were hung on the trees of four sweet orange varieties during the major citrus fruiting seasons of 2003 and 2004. Results. Species of Ceratitis dominated in the fruit fly samples collected. Both the imported and locally made baits caught significantly higher numbers of fruit flies than the non-baited control. There was no significant difference between the populations of fruit flies caught by the two baits during the studies. The decreasing order of varieties according to trapped fruit fly numbers for both the imported and locally made baits were: Washington navel > Parson Brown > Valencia late > Agege-1. The fruit fly numbers observed on Washington navel were significantly higher than those of Agege-1 and Valencia late. Discussion. Our results show the effectiveness of the locally made protein bait in fruit fly monitoring and management. Varietal differences also played a part in determining the extent of fruit fly attacks on sweet oranges.

Results of a field survey of certain host-related and off-the-shelf compounds as possible attractants for the black fly, Simulium arcticum (Malloch) (IIS-10.11) (Diptera: Simuliidae), are reported. Silhouette traps were baited with carbon dioxide and candidate attractants in an incomplete randomised block design. Carbon dioxide alone exerted a strong attractant effect on this species. Both acetone and crude whole body odour of cattle (tested in combination with carbon dioxide) were significantly more attractive than carbon dioxide alone (control). Although bovine urine produced larger catches than control (carbon dioxide only) traps, the effect was not statistically significant. Other odours tested in combination with carbon dioxide, including fractions of the crude bovine odour and l-octen-3-ol (a potent tsetse fly attractant), were without apparent attractant effect when compared to the carbon dioxide-only control.

This review concentrates on air-borne chemical cues that blood-seeking mosquitoes use to locate a host. A distinction is made between short- and long-range attraction. Carbon dioxide is involved in both processes. It activates and attracts mosquitoes. The latter function is only observed in combination with an odorous organo-chemical. Other olfactory cues are primarily involved in long-range attraction. Bodily emanations from the host that contain olfactory cues can be divided into three groups: Skin emanations, exhaled air and urine. Each of these is attractive to mosquitoes, but there is little knowledge about the chemical compounds that cause the attraction. Lactic acid in the presence of CO2 is attractive, and lactic acid-sensitive neurosensilla are present on the antennae. Other host-produced chemicals are also attractive, but chemical identification and subsequent confirmation of attractiveness for mosquitoes has not been reported. Host preference in mosquitoes is species-specific and varies from highly specific to opportunistic. Attraction is likely to be caused by a mixture of several compounds. Synergism may be an important way of increasing the effect of separate chemical cues.

EAG recordings revealed that from the six substances isolated so far from pheromone glands of Marnestra brassicae females, only (Z)-11-hexadecenyl acetate (Z11-16Ac), (Z)-9-hexadecenyl acetate (Z9-16Ac) and (Z)-11-heptadecenyl acetate (Z11-17Ac) are perceived by the males. This suggests that these substances may be female sex pheromone components.

The male olfactory sensilla also respond to (Z)-9-tetradecenyl acetate (Z9-14Ac) and (Z)-11-hexadecenol (Z11-160H), which are sex attractant constituents of various closely related species, but act as strong attractant inhibitors on M. brassicae males. This sensitivity to Z9-14Ac and Z11-160H is suggested to enhance the males' possibility to discriminate between conspecific and non-conspecific females.

Single sensillum recordings revealed that in 90% of the male antennal sensilla trichodea tested, three cell types (Types A, B, and C) were active. In the remaining 10% only B and C action potentials were seen. The Type C cells are exclusively responsive to the major pheromone component Z11-16Ac. The Type C cells are activated by the attractant inhibitors Z9-14Ac and Z11-160H, and to a small extent by Z11-16Ac. Responses to mixtures of these substances revealed that addition of Z9-14Ac and Z11-160H to Z11-16Ac changed the activity of the A cells only and did not affect the activities of the A and C cells. It is concluded that volatiles which exclusively or predominantly activate the Type B cells induce avoidance behaviour in the males, whereas substances activating the Type C cells evoke sexual behaviour and are attractive. This offers possibilities for relatively rapid electrophysiological determination of substances inducing sexual or avoidance behaviour. The function of the A cells is not yet clear. These cells respond to low concentrations of Z11-16Ac and Z11-160H, which may enhance the males' capacity to distinguish conspecific from non-conspecific females at a distance, when concentrations are low and the C and B cell activities are small.

It is suggested that cells sensitive to Z9-16Ac and Z11-17Ac are present in a limited number of sensilla only.

Steam-distilled floral oils (essences) from several species of Theobroma(Sterculiaceae) (T. cacao Linneaus, T. simiarum Donn. Smith, T. mammosum Cuatr. & Leon, and T. speciosum Willd.) were tested using McPhail traps, in an abandoned Costa Rican cocoa plantation to determine their levels of attraction for flying insects. In each of the three bioassays (two successive dry seasons and one intervening rainy season), the traps were inoculated with floral scents at 1, 10, and 100 ppm, while controls were inoculated with a 10% solution of chloroform solvent in distilled water. Of a total of 223 Diptera captured in all three bioassays, only 5% were found in the controls, indicating attraction to the floral oil. About 72% of all Diptera captured were Cecidomyiidae, of which three species, Mycodiplosis ligulata Gagne, Aphodiplosis triangularas (Felt.) and Ledomyia sp., comprised 59% of the total. Eighty-eight per cent of all midges captured were females. Only 7% of the total were known cocoa-pollinating midges of Ceratopogonidae, and all of these were females. Sixteen per cent were Phoridae, known pollinators of the allied genus Herrania in Costa Rica. Although the chemical composition of floral oils varies greatly among the species of Theobroma, no discernible differences were found in the attraction of midges to floral oils tested. While floral fragrances in Theobroma species may represent a generalized adaptation for dipteran pollination, small numbers of several species of Trigona bees (Hymenoptera: Apidae: Meliponinae) were also attracted to the floral oils.

The use of fish meal and detergent water has been shown to be simple, economic and reliable for sampling of shootfly populations. Various mixtures of fish meal with other ingredients were evaluated. The most potent mixture was fish meal-yeast-ammonium sulphide, but generally fish meal alone was adequate and the most readily available attractant. The attractance of fish meal was found to be related to its degradation; it increased from the first to the third or fourth day, and then decreased. The chemicals responsible for the attractance of fish meal have yet to be identified, but in all probability they may be the amines resulting from biodegradation of the meal.