A. K. Burditt’s research while affiliated with United States Naval Research Laboratory and other places

Field tests on attraction of Caribbean fruit flies to 15 times 20 cm colored sticky traps releaved a clear preference for orange, followed by yellow and yellow‐green. Lower capture rates were obtained for dark green, blue, red, black, and white. Reflectance spectra of painted surfaces were determined and it was noted that fly capture rates were directly related to the proportion of light reflected in the 580–590 nm region. Attraction appeared to depend primarily upon the hue rather than the intensity of emission. Responses to orange were considered to indicate fruit‐seeking rather than foliage‐seeking behavior because a disproportionate number of females was captured (3:1 ♀ ♂ ratio), because foliage normally reflects maximally in the yellow‐green rather than the orange region, and because a variety of host fruit reflects strongly in the orange region of the spectrum. RÉSUMÉ ETUDES SUR LE TERRAIN DES PREFERENCES DE LA MOUCHE DES FRUITS DES CARAÏBES ANASTREPHA SUSPENSA A L'EGARD DE DIVERS PIEGES COLORES Des tests sur le terrain concernant l'attraction de la Mouche des fruits des Caraïbes à l'égard de pièges adhésifs colorés mettent en évidence une nette préférence de l'insecte pour la couleur orange, suivie de près par le jaune et le jaune‐vert. Les taux de capture les plus faibles ont été obtenus par des pièges de couleur vert‐foncé, bleue, rouge, noire et blanche. Le spectre de la lumière réfléchie par les surfaces peintes a été précisé et il a été remarqué que les taux de capture des mouches étaient en rapport direct avec la quantité de lumière réfléchie dans la gamme de 580–590 nm, mais l'attraction semblait dépendre en premier lieu de la couleur plutôt que de l'intensité de l'émission. Les réponses à la couleur orange semblent indiquer un comportement de recherche du fruit plutôt que recherche du feuillage, ceci en rapport avec la capture d'un plus grand nombre de femelles (30/10), et parce que le feuillage réfléchit normalement au maximum dans le jaune vert plutôt que dans l'orange, alors qu'une variété de fruit‐hôte de cet insecte réfléchit fortement dans la zone du spectre correspondant à l'orange.

(E,E)- and (E,Z)-8,10-Dodecadien-1-ol acetates were identified in a 1∶4.3 ratio in the extract of abdominal tips of female filbert-worm moths,Melissopus latiferreanus (Walsingham). The identifications were based on electroantennogram (EAG) analysis, gas chromatography, mass spectrometry, ozonolysis, and synthesis. TheE,Z isomer produced the stronger EAG response. In the field tests of various ratios ofE,E∶E,Z, the ratio found in the extract captured the most males. The pureE,E isomer initially was not attractive by itself (<0.1%E,Z) but became attractive after a few days, presumably because of isomerization. TheE, Z isomer (<0.1%E,E) was attractive initially, but this compound might have isomerized faster than theE,E isomer. A study of the isomerization showed that regardless of the initial mixture of 8,10-dodecadien-1-ol acetate isomers, almost complete equilibration existed after one month. The equilibrium mixture consisted of 9%Z8,E10, 65%E8,E10, 23%E8,Z10, and 3%Z8,Z10. Concentrations in rubber septa (1∶4 ratio ofE,E toE,Z) of 0.03-3.0 mg/septum produced equivalent trap catches.

Cyclohexyl phenylacetate, a lure for male and female checkered flower beetles, Trichodes ornatus Say, impregnated on rubber septa was effective for 6 weeks in the field. Beetle captures in traps baited with septa containing 200–400 mg of the lure were statistically equal. Septum containing 400 mg lure initially will lose ca. 200 mg through evaporation by the 43rd day; thus, two baits suffice for the beetle’s principle flight period which lasts from early June to mid-August in Washington.

The maximum parasitism rate by Doryphorophaga doryphorae (Riley) of the Colorado potato beetle (CPB), Leptinotarsa decemlineata (Say), approached 75%. However, this occurred in late August and September, when the CPB larvae had already damaged the crop. The effectiveness of the parasite was limited by its low abundance during the first generation of the CPB. Although 9, 30, and 61% of the 2nd, 3rd, and 4th larval instars of CPB, respectively, were parasitized, parasitic maggots did not develop until the fourth-stage CPB larva entered the soil to pupate. Thus, there was a delay of about 7 days in fly emergence from hosts that had been parasitized as 2nd-instar rather than 4th-instar CPB larvae. We estimated that as much as 39% of the emerging fly were delayed over a 7-day period

Doryphorophaga doryphorae (Riley) is a parasite of the Colorado potato beetle, Leptinotarsa decemlineata (Say). In our tests, male parasites emerged a few days earlier than females, with a 3:1 numerical advantage in the first 3 days. The female parasite is larviparous and the prelarviposition period averaged 7.8 days. The average larviposition period was 21 days, with the longest period being 45 days. On the average, the female parasite larviposited 215 times in her lifetime and at the rate of 10.8 times per day. When hosts were withheld for a few days and then made available to the flies, the rate of parasitism and superparasitism was substantially higher than normal for a brief period. Under laboratory conditions, the female did parasitize 1st-instar CPB larva, although at a lower rate (3 to 11%) than it did the other larval instars

Various fruits were fumigated with ethylene dibromide (EDB) in a 50 ft3 chamber for 2 hours, aerated 1 hour via an exhaust blower, and stored. A temperature of about 75°F was maintained during all stages via air conditioning. EDB was applied either at a dose level of 8 ov/1000 ft3, which is the level currently used commercially as a quarantine treatment for grapefruit being shipped from Florida to Japan, or at 16 ov/1000 ft3 in the case of fruits for which no effective dosage has been established. Samples of fruit were taken at various intervals after fumigation and assayed for residues of EDB by using steam distillation for separation and purification and gas chromatography with an electron capture detector to quantitate. Inorganic bromides were not determined. The data (see table) indicate that the amount of EDB absorbed and retained is highly dependent on both the type of fruit fumigated and the amount of fumigant applied.

These reported data were obtained in a continuing series of tests of toxicants for use against tropical fruit flies of quarantine importance. The Caribbean fruit flies, Anastrephasuspensa (Loew), used in the tests were from the insect colony established at the Subtropical Horticulture Research Unit at Miami, Florida! Tests were done in empty commercial semitrailer vans (ca. 713 volume) located at various trailer and container leasing firms in the Miami area. One-wk-old adult flies were caged in fabricated, open-ended, screened, pint ice-cream containers (4 cages/test, ca. 200 flies/cage), and the cages were attached to three walls and the ceiling of the van. Insecticides were formulated (1) as dusts (HiSil 233 carrier) and propelled with CO2 gas; (2) as aerosols formulated with Freon or with water and propane/isobutane and released from aerosol pressurized cans; or (3) as E. C.’s applied with Micro-gen or Microsol sprayers. Rates of application were as stated in the table. The exposure to the toxicants lasted 30 minutes, 10 with the van doors closed and the other 20 with one door open. Insect knock down (K.D.) counts were made when the cages were removed at 30 minutes. Mortality counts were made at 24-hr postexposure. Average temperatures during the exposure and holding periods was 25°C. Except when KD and 24-hr mortality were very low (i.e., Lilly L-28 in 1977), all tests were replicated at least twice. All KD and 24-hr mortality counts were corrected by using Abbott’s formula and averaging.

Fluorescent orange sticky traps (15 times 20 cm) reflecting maximally at 590 nm captured significantly more Caribbean fruit flies than nonfluorescent orange traps. Fluorescent traps with reflectance peaks at 510 and 610 nm also tended to capture more flies than the plain orange traps. Fly capture rates were directly related to the proportion of total light reflected in the 580–590 nm region and to the intensity of light of this hue. The fluorescent orange paint combined these features (optimal hue and high‐intensity emission). A disproportionate number of the captured flies were females (70%), as only ca. 50% of the adults reared from field‐infested fruit were females. Most (80%) of the captured females were reproductively mature. These data support previous indications that responses to orange panels represent fruit‐seeking rather than foliage‐seeking behavior. The relevance of these findings is discussed in relation to fruit fly detection programs. RÉSUMÉ RENFORCEMENT DE PIÈGES ATTRACTIFS VISUELS POUR ANASTREPHA SUSPENSA ( THE CARIBBEAN FRUIT FLY) PAR EMPLOI DE COULEURS FLUORESCENTES Des pièges adhésifs (15 times 20 cm) fluorescents de coloration orange, dont la réflexion maximale se situe à 590 nm, capturent significativement plus de cette mouche des fruits (Anastrepha suspensa) que des pièges oranges non fluorescents. Des pièges fluorescents avec maxima de lumière réfléchie à 510 et 610 nm tendent aussi à capturer plus de mouches que des pièges oranges simples. Les taux de capture de mouches sont en relation directe avec la proportion de lumière totale réfléchie dans la région spectrale 580–590 nm et avec l'intensité lumineuse dans cette longueur d'onde. La peinture fluorescente orange combine ces deux avantages (couleur optimale et émission de forte intensité). Un nombre disproportionné des mouches capturées sont des femelles (70%) alors que seulement 50% environ des mouches issues de fruits naturellement infestés sont des femelles. La majorité (80%) des femelles capturées étaient génitalement mûres. Ces divers faits sont en accord avec les données antérieures établissant que les réponses aux panneaux oranges correspondent à un comportement de recherche de fruits plutôt que de recherche de feuillage. La valeur de ces observations est discutée en relation avec les programmes d'avertissements relatifs à la mouche des fruits.