Volatiles from Botrytis cinerea‐infected and healthy berries of Vitis vinifera influence the oviposition behaviour of Epiphyas postvittana

Interactions among plants, plant‐feeding insects, and plant – pathogenic fungi are partially mediated by volatile compounds. Herbivorous insects use sensory cues to choose host plants for feeding and/or oviposition that are likely to support survival and development of progeny. It is known that some fungus‐induced alterations in plants can modify plant volatiles, which are recognized by the olfactory receptors of the insect, either as an attractant or as a deterrent. We tested for the presence of behaviour‐modifying volatiles emanating from the berries of Vitis vinifera L. (Vitaceae) infected with Botrytis cinerea Pers. (Helotiales). We tested the olfactory behaviour of adults of Epiphyas postvittana Walker (Lepidoptera: Tortricidae) to these volatiles using two‐choice and wind‐tunnel experiments. We hypothesized that olfactory cues influence E. postvittana's oviposition behaviour. We found that volatiles emanating from B. cinerea‐infected berries did not significantly attract the gravid females of E. postvittana; consequently, they laid significantly fewer eggs on infected berries. Furthermore, significantly fewer females of E. postvittana were found attracted to infected berries in the wind tunnel assay. Ethanol and 3‐methyl‐1‐butanol were abundant in B. cinerea‐infected berries. Oviposition assays made with laboratory standards of ethanol and 3‐methyl‐1‐butanol confirmed their role in regulating the olfactory behaviour of E. postvittana site selection.     

Mutualism between a phytopathogenic fungus (Botrytis cinerea) and a vineyard pest (Lobesia botrana). Positive effects on insect development and oviposition behaviour

In vineyards, larvae of the grape berry moth (Lobesia botrana) favour the development of the grey mould fungus Botrytis cinerea. To study the possibility of a mutualistic relationship between these organisms, we investigated the effects of the fungus on the development and oviposition behaviour of the insect. Larvae were reared on whole plants infected or uninfected with the fungus, or on an artificial diet containing either infected grape berries or the mycelium. The presence of the fungus consistently led to a reduction in the duration of insect development (4–6 d) and mortality (20–67 %). The fecundity increased from 12 to 76 %. Moreover, the fact that the females laid eggs preferentially on fungus-infected grape berries confirms the mutualistic association between these organisms. The fungus alone contributed to the positive effects. We showed the existence of a mutualistic relationship between the two organisms which are both damaging to vineyards.     

Fecundity and juvenile survival of shape Bembidion lampros and Tachyporus hypnorum

Fecundity and development from first instar larvae to adult beetles were studied for Bembidion lampros Herbst (Coleoptera; Carabidae) and Tachyporus hypnorum F. (Coleoptera; Staphylinidae). Both species reproduce in arable fields, where they are known to contribute to the natural control of cereal aphids. They are univoltine and have similar life cycles and development times. T. hypnorum females laid approximately 3 times more eggs than B. lampros females. Relative lifetime fecundity of B. lampros was very low with an average of 10 eggs per female. Based on the time where half of the populations had dispersed from the overwintering sites into an arable field B. lampros started egg-lay 100°D (°C>9) and T. hypnorum 200°D (°C>3) after dispersal. Mortality in the juvenile stages was found to be an important factor in the population dynamics of both B. lampros and T. hypnorum. The survival from first instar larvae to adults was on average 34% for B. lampros independent of soil type, 21% for T. hypnorum developed in sandy soil and 49% when developed in clayey soil under semi-field conditions. Enlargement of B. lampros and T. hypnorum populations to increase the natural control of aphids during their establishment in cereal fields may be possible if the conditions for juvenile development are improved.     

Prey finding by larvae and adult females of shape Episyrphus balteatus

The prey-location behaviour of larvae of Episyrphus balteatus DeG. (Dipt.: Syrphidae) was investigated in two different experimental set-ups. First instar larvae exhibited directed search over short distances, guided by olfactory cues from aphids, but not from honeydew. However, second and third instars did not respond to aphid-plant-complex odours in a 4-arm-olfactometer. Aphid extracts, honeydew and sucrose were found to be feeding stimulants for the larvae. The oviposition behaviour of female syrphids was investigated in a series of two-choice experiments: females were able to evaluate aphid numbers and adjust oviposition rates accordingly, with higher prey numbers eliciting increased oviposition, even when the aphids were removed at the start of the experiment. The presence of conspecific syrphid larvae did not inhibit oviposition when the females were deprived of suitable oviposition sides before the experiments were conducted.     

Interspecific competition between the braconid endoparasitoids Glyptapanteles porthetriae and Glyptapanteles liparidis in Lymantria dispar larvae

The effect of interspecific competition between the solitary endoparasitoid Glyptapanteles porthetriae Muesebeck (Hymenoptera: Braconidae) and the gregarious Glyptapanteles liparidis Bouché (Hymenoptera: Braconidae), was investigated in larvae of Lymantria dispar L. (Lepidoptera: Lymantriidae). Host larvae were parasitized by both wasp species simultaneously in premolt to the 2^nd or the 3^rd host instar or in an additional approach with a 4-day delay in parasitization by the second wasp species. Host acceptance experiments revealed that both wasp species do not discriminate between unparasitized host larvae and larvae parasitized previously by the same or the other species. In more than 90% female wasps parasitized the larva they encountered first. During the period of endoparasitic development, larvae of the competing parasitoid species never attacked the egg stage of the other species. When host larvae were parasitized simultaneously by both wasp species, the rate of successful development of both species depended on the age of the host larva at the time of its parasitization; G. liparidis emerged successfully from 44% of host larvae parasitized during the premolt to 2^nd instar, G. porthetriae from 28%, and in 20% of the hosts both parasitoid species were able to develop in one gypsy moth larva. However, when host larvae were parasitized simultaneously during premolt to the 3^rd instar, G. liparidis was successful in 90% of the hosts, compared to 8% from which only G. porthetriae emerged. In the experiments with delayed oviposition, generally the species that oviposited first succeeded in completing its larval development. Larvae of the species ovipositing with four days delay were frequently attacked and killed by larvae of the first parasitizing species or suffered reduced growth. As the secondary parasitoid species, G. porthetriae-larvae were never able to complete their development, whereas G. liparidis developed successfully in at least 12,5% of the multiparasitized host larvae. Thus, multiparasitism of gypsy moth larvae by both Glyptapanteles species corresponds to the contest type; however, G. porthetriae is only able to develop successfully as the primary parasitoid of young host larvae.     

Comparative headspace analysis of cabbage plants damaged by two species ofPieris caterpillars: consequences for in-flight host location byCotesia parasitoids

Headspace composition, collected from intact cabbage plants and cabbage plants infested with eitherPieris brassicae L. orP. rapae L. (Lepidoptera: Pieridae) first instar larvae, was determined by GC-MS. Twenty-one volatiles were identified in the headspace of intact plants. Twenty-two volatiles were identified in the headspace of plants infested byP. brassicae larvae, 2 of which, Z-3-hexenyl butyrate and Z-3-hexenyl isovalerate, were not detected in the headspace of either intact orP. rapae damaged plants. In the headspace of the latter, 21 compounds were identified, all of which which were also produced by intact plants. No significant quantitative differences were found between headspace composition of the plants damaged by one or the other caterpillar species. Major differences between intact and caterpillar-damaged plants in contribution to the headspace profile were revealed for hexyl acetate, Z-3-hexenyl acetate, myrcene, sabinene and 1,8-cineole. The larval endoparasitoidCotesia glomerata L. was attracted by the volatiles emanating fromB. oleracea damaged byP. brassicae first instar larvae.C. rubecula L., a specialized larval endoparasitoids ofP. rapae, was attracted by the volatiles released from theB. oleracea-P. rapae plant-host complex. This shows that cabbage plants kept under the conditions of headspace collection produce attractive volatiles for both parasitoids.     

蚊幼虫病原真菌贵阳腐霉的生物学研究

为了开发灭蚊真菌贵阳腐霉Pythiumguiyangense用于蚊虫防治,对贵阳腐霉生物学特性进行了研究。采用菌丝生长率、真菌产孢情况以及对致倦库蚊Culexquinquefaciatus1龄幼虫的毒力作为评价的指标。测试了7种人工培养基、7种单糖、7种氮源、真菌生长所需的pH范围和温度范围、以及4种光-暗比的光照程序对真菌的影响。结果证明该真菌生长的适合温度为5℃～35℃,最佳温度为25℃～30℃;适合pH范围是5～12;在pH9～11范围内菌丝和游动孢子生长最好;测试的人工培养基中,按照菌丝生长速度从高到低排列,依次为Czapek’SFE、PYG、KPYG2、SDAY、CMA和PDA。其中从真菌的游动孢子形成量和对蚊幼虫的毒力来看,最佳培养基为SFE;葡萄糖、果糖、乳糖、蔗糖、麦芽糖、甘露糖和可溶性淀粉都是本真菌的合适碳氢营养源;含有机氮的培养基比含无机氮的培养基好;不同的光照程序没有表现明显的影响,但是观察到紫外光对本真菌有明显的抑制作用。     

Potential application of the entomopathogenic fungus, shape Nomuraea rileyi, for control of the corn earworm, shape Helicoverpa armigera

The entomopathogenic fungus, Nomuraea rileyi, caused 90.5–100% mortality in fourth-instar larvae of the corn earworm, Helicoverpa armigera, when applied at 10⁷ conidia/ml to corn silks, and leaves of soybean, tomato and chrysanthemum. The LT₅₀ was 5.9–6.7 days. The fifth-instar larvae showed a mortality of 94.6% on soil with 20% water content, and 41.7% on 10% water content when the soil surface was sprayed with 10⁸ conidia/ml suspension. Five fungicides, eight insecticides and nine herbicides, which are commonly used in corn fields, were evaluated for inhibition to conidial germination by a paper disk test. Among them, only two fungicides, viz., maneb and propineb, were highly inhibitory, while insecticides and herbicides examined were not inhibitory to the fungus. Field applications of N. rileyi conidial suspension to neonate larvae were found to be as effective as 40.46% carbofuran (EC) at 800-fold dilution in controlling corn earworm based on marketable ears. It is thus suggested that N. rileyi has potential to be a microbial control agent for this insect.     

斜纹夜蛾幼虫感染莱氏野村菌后的抗氧化酶活性变化

【目的】研究斜纹夜蛾Spodoptera litura幼虫感染莱氏野村菌Nomuraea rileyi后的抗氧化防御机制。【方法】通过测定斜纹夜蛾各龄幼虫超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和过氧化物酶(POD)等的活性,探讨染菌后不同侵染阶段,幼虫抗氧化酶活性的变化趋势和不同接种方法对抗氧化酶活性的影响。【结果】在斜纹夜蛾染菌幼虫和未接种幼虫(对照)中均未测出POD活性;各龄幼虫在接种莱氏野村菌后SOD和CAT活性显著高于对照,但随着侵染过程的进行,2-3龄幼虫的SOD和CAT活性在16 h左右达峰值后迅速降低,而4-5龄幼虫SOD和CAT活性自染菌初期增强后,变化较平缓,至60-72 h后才低于对照。喷雾法与浸蘸法接种后,各龄幼虫SOD和CAT活性显著高于对照,且对于2-3龄幼虫,浸蘸法对抗氧化酶活性的影响显著高于喷雾法,而对于4-5龄幼虫而言两处理方式之间活性差异不显著。【结论】斜纹夜蛾感染莱氏野村菌后,其体内抗氧化酶活性变化很大,SOD和CAT活性先升后降,且其变化趋势与幼虫所处的发育阶段密切相关。在体壁接种量相当的情况下,浸蘸法对2-3龄幼虫SOD和CAT活性的影响大于4-5龄幼虫。     

Biological characterization of an English granulovirus from the summer fruit tortrix moth, Adoxophyes orana

Adoxophyes orana granulovirus (AdorGV) was isolated from overwintering larvae in an orchard in Kent, in the UK. The developmental time of each A. orana instar was determined by measuring the size of the head capsule. The susceptibility of the larvae to the English isolate of AdorGV was evaluated in laboratory bioassays using inoculation by microdroplet feeding and applied dose assays. A series of bioassays were performed to determine LD(50) and ST(50) values for first, fourth and fifth instar larvae. The median lethal doses ranged from 30 occlusion bodies in first instar to 1.36 x 10(6) in fifth instar. The median survival time decreased the later the larvae were infected and ranged from 37 days in first instar to 24 days in fifth instar. Approximately half of the infected larvae released a discharge rich in occlusion bodies from their posterior end prior to death. Approximately 85% of larvae attempted pupation and died as larva-pupa intermediates.     

虫草菌感染虫草蝠蛾幼虫的研究

本文叙述了虫草菌在自然条件下感染虫草蝠蛾幼虫的过程和特性,主要内容包括自然感染的虫龄和影响感染的生态因子。     

The time--mortality response of mosquito larvae infected with the fungus Culicinomyces

In laboratory experiments with Culicinomyces, the time of death of infected Anopheles hilli larvae decreased as the concentration of conidia to which they were exposed increased. At a concentration of 10³ conidia/ml, most first instar and third instar larvae died later than 2 days after exposure and the majority of dead specimens developed external sporulation on the exterior cuticle. On the other hand, at a concentration of 10⁵ conidia/ml, more than 60% of first and third instar larvae died within 2 days of exposure. Very few of these larvae developed external sporulation and it appears that most of them died after penetration by the fungus through the gut cuticle but before the hemocoel was colonized by mycelium. The reason for this rapid death at high concentrations of inoculum is not known, but it is thought that it may be caused by toxic substances associated with the invading hyphae which only attain a lethal titer when massive invasion originates from large numbers of conidia.     

Larval morphology of Metaphycus flavus and its role in host attachment and larval cannibalism

Metaphycus flavus (Howard) (Hymenoptera: Encyrtidae) is a facultatively gregarious endoparasitoid of soft scales (Hemiptera: Coccidae). When it develops in superparasitised hosts, the larvae often attack and consume brood mates six or more days post oviposition. Under our laboratory conditions (25±1°C and 14 hours of light followed by 18±1°C and ten hours of darkness in 50-70% R.H.), M. flavus eggs hatched three days after oviposition. Measurements of the mandibles and tentorium indicate there are four larval instars, and M. flavus reaches the fourth instar by day six post oviposition, and pupates on day eight. Thus, cannibalism among M. flavus larvae occurs during the fourth instar. During this instar, M. flavus larvae separate from their attachment to the scale cuticle, to which they were tethered by a respiratory structure during the previous three larval instars. Once detached, they are free to move within the scale, which increases the probability of larval encounters and aggressive behaviours. Moreover, the mandibles of the fourth instar are better adapted for fighting than are those of the first three larval instars, since they are larger and more sclerotized. The cranium and mouthparts of M. flavus have four different types of sensory organs, some of which are almost certainly olfactory, an unexpected function for a larva that presumably is surrounded by an aqueous medium where gustatory sensilla would seem to be more appropriate. The cranium also bears two pairs of what appear to be secretory pores.     

Stage-specific control of grape berry moth, Endopiza viteana (Clemens) (Lepidoptera: Tortricidae), by selective and broad-spectrum insecticides

The insect growth regulators (IGRs) tebufenozide and methoxyfenozide and the broad-spectrum insecticides azinphosmethyl, carbaryl, and fenpropathrin were compared for their activity against adult, egg, and larval stages of the grape berry moth, Endopiza viteana (Clemens) (Lepidoptera: Tortricidae), under laboratory and vineyard conditions. Adult mortality was not affected by exposure to field-equivalent rates of tebufenozide or methoxyfenozide on grape clusters, whereas all the broad-spectrum compounds significantly reduced adult survival, compared with the untreated controls. Surviving adult moths laid significantly more eggs on berries treated with the IGRs than on berries treated with any of the broad-spectrum insecticides. Survival of these eggs through to late larval and pupal stages was significantly lower on methoxyfenozide-treated grapes than on untreated grapes, and no pupae were found when grapes were treated with azinphosmethyl or fenpropathrin. Neither of the growth regulator insecticides limited egg eclosion or larval development by E. viteana when insecticides were applied before egg laying, whereas broad-spectrum insecticides were effective against both eggs and neonates at this timing. When applied after egg eclosion, all insecticide treatments significantly reduced survival of grape berry moth larvae. Under vineyard conditions, berries with 1-d-old residues of tebufenozide or methoxyfenozide received more E. viteana eggs than berries treated with broad-spectrum compounds. After aging for 7 or 14 d, no significant effects on E. viteana survival were detected among treatments. Whereas broad-spectrum insecticides provide control of multiple life stages of E. viteana, integration of tebufenozide or methoxyfenozide into vineyard management programs for control of this pest will be most successful if applications are timed for egg hatch.     

Behavioural responses of larvae of Colorado potato beetle,Leptinotarsa decemlineata (Coleoptera: Chrysomelidae), to host plant volatile blends attractive to adults

Abstract

• 1 Orientation of second‐ and fourth‐instar Colorado potato beetle (CPB) Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae), to volatiles emitted from a solanaceous host, potato, and seven synthetic blends or three individual chemicals emitted by potato plants were investigated in laboratory bioassays.
• 2 Both second‐ and fourth‐instar CPB were attracted to intact and mechanically damaged (MD) potato foliage. When offered a choice between intact and MD foliage, no preference was observed.
• 3 Among seven synthetic blends tested (of which six are attractive to adult CPB), second‐ and fourth‐instar CPB were attracted only to a single three‐component blend comprising (±)‐linalool, methyl salicylate, and (Z)‐3‐hexenyl acetate. Individual compounds and two‐component blends were inactive. No significant difference was noted between larval responses to the attractive synthetic blend vs. MD potato foliage.
• 4 Second‐and fourth‐instar larvae had similar thresholds for behaviour for the three‐component blend (50 µg source load). Female CPB were attracted to source loads 10× below the larval threshold (5 µg). Male CPB were the most sensitive life form tested with a behavioural threshold at 0.5 µg source load which was 10× and 100× below female and larval thresholds, respectively
• 5 This is the first report of a synthetic chemical attractant for CPB larvae. As both larval and adult CPB are attracted to a single chemical blend, the usefulness of the attractant as a component of an attracticide or ‘push‐pull’ strategies for management of pestiferous populations is enhanced.

     

Damage Patterns caused by Lygocoris spinolae (Hemiptera: Miridae) on ‘Campbell Early’ Grapes

The phenology and damage patterns of Lygocoris spinolae (Meyer-Dür) on ‘Campbell Early’ grape were examined in different grape development stage of inflorescence formation, blooming, and berry set. Nymphs fed on newly unfolding leaves of shoot tip before inflorescence formation. As the inflorescences were clearly visible, nymphs on leaves moved to flower clusters. Sting spots with brown color occurred at sucking sites of leaves, then expanded to hole as the leaves developed, and resulted in leaf malformation. The nymphs on flower clusters sucked developing florets, which induced the drying of florets followed by defoliation. After flower caps had fallen, L. spinolae fed on young berries causing blackening of berry skin around the sting. The blackening of berry skin changed to corky-scarred tissue as the berry developed. L. spinolae feeding significantly reduced the number of berries per cluster in all grape stages. A few berries became corky-scarred or shot berries when fed at inflorescence formation period. Feeding at blooming caused shot berries with low rate of corky-scarred berry. Most of the berries were corky-scarred or became shot berries when fed at berry set. Feeding by adults caused the same damage patterns as nymphs. Heavy damages were observed where L. spinolae were introduced after inflorescence formation: reduced number of berries per cluster by 35.0 to 99.1% at blooming and by 80.0% at berry setting depending on L. spinolae densities.     

Method for quantitative sampling of fungus gnat larvae in soilless growing media

A simple method is described for separating fungus gnat larvae from soilless growing media. Samples are first fractionated by water flotation with an inverted flask procedure and then the sediment is degassed under reduced air pressure and fractionated in magnesium sulfate (MgSO4) solution (density of 1.12 g cm(-3)). Fungus gnat larvae with only a small amount of contaminating debris are recovered from the surface of the MgSO4 solution for immediate counting or for preservation in alcohol. In evaluations of different commercial soilless growing media with a range of components, two repetitions of the water flotation step eliminated 20-40% of the dry weight of samples and virtually all of the perlite from further processing. Repeating both the water and MgSO4 flotations a third time only marginally improved the recovery of larval fungus gnats, Bradysia sp. nr. coprophila, added to pasteurized media. Extraction efficiency differed between instars and, to a lesser extent, between different types of media. Across three commercial soilless media tested, recovery was 24-33% for first, 68-85% for second, 85-95% for third, and 98-100% for fourth instars. Within combinations of media and instar, recovery was consistent. With this method, a 400-cm3 sample can be processed and be ready for counting in 1-1.5 h; samples can also be processed in batches or in assembly-line manner to process many samples per day. The method may also prove useful for quantitative recovery of shore fly larvae, thrips pupae, and other arthropods from soilless growing media.     

Host selection and survival of the parasitoidEncarsia formosa on greenhouse whitefly,Trialeurodes vaporariorum, in the presence of hosts infected with the fungusAschersonia aleyrodis

Successful control of greenhouse whitefly may be achieved by complementary activity of the parasitoidEncarsia formosa and the fungusAschersonia aleyrodis. One way to obtain an additive mortality effect of both entomopathogen and parasitoid would be achieved by the selection of healthy hosts by the parasitoid and rejection of fungus-infected hosts. Third and fourth instar larvae ofTrialeurodes vaporariorum which had been treated with a spore suspension ofA. aleyrodis 0, 4, 7, 10 or 14 days beforehand, were presented to female parasitoids. The parasitoids adopted the oviposition posture on untreated hosts as well as on treated hosts, irrespective of the different stages of infection in the hosts. However, significantly more hosts were parasitized byE. formosa in the control treatment than in the fungal treatment. The parasitoids offered treated hosts, showed rejection behaviour after probing on hosts showing detectable signs of infection (containing hyphal bodies or mycelium in the haemolymph). For instance, when hosts were offered seven days after spore treatment, the parasitoids showed an oviposition posture on a total of 83 (95.4%) out of 87 infected larvae, but laid only 4 eggs (4.6%). In contrast, on 48 (94.1%) out of 51 noninfected (or showing no detectable signs of infection) hosts an oviposition posture was adopted and 40 eggs (78.4%) were found after dissection. When infected hosts were encountered the oviposition posture lasted less than 1′40″ while rejection of non-infected hosts occurred after more than 1′40″. Other experiments were carried out offering treated hosts for 24 h to the parasitoids. The hosts were dissected afterwards. Again, significantly more eggs were laid in the non-infected hosts. When hosts were parasitized shortly after fungal spore treatment they were colonized by the fungus and the parasitoids did not develop. Transmission of the entomopathogen after probing infected hosts was observed to a limited extent. In conclusion,A. aleyrodis andE. formosa can be used together in a glasshouse situation. The parasitoid will be most effective when introduced more than seven days after application ofA. aleyrodis, because from that time onwards it is able to detect and reject fungus-infected hosts.     

桃蚜脱皮对球孢白僵菌毒力的影响

室内测定了球孢白僵菌Beauveria bassiana BBSG8702菌株对桃蚜Myzus persicae 若蚜的毒力,并分析了若蚜脱皮与白僵菌有效侵染之间的关系。在21℃、1×10⁶/mL孢子浓度下, 1～4龄若蚜感菌后的累积死亡率分别为10.1%、2.1%、3.1%和40.2%,明显低于同样条件下成蚜的感菌死亡率(98.4%)。在若蚜各龄感菌死亡的个体中,1～4龄中分别有8.1%、50.0%、44.4%和98.0%的若蚜在死亡前发育到成蚜,且都能产下正常发育的后代。若蚜的感菌死亡率与接菌后到第一次脱皮的时间密切相关,脱皮早则感菌死亡率低,反之亦然。但试验中也发现有部分若蚜特别是低龄若蚜感菌后未完成第一次脱皮便死亡。观察了桃蚜在1、4龄早期感染球孢白僵菌后的发育、存活和生殖情况,结果表明：1、4龄早期若蚜接菌后第一次脱皮的时间早于未接菌若蚜,但提前幅度少于5%,在羽化为成蚜之前被致死的概率分别只有4.1%和0,在羽化为成蚜后8天内的生殖率与未接菌蚜虫的无明显差异。这些结果表明,若蚜的脱皮,尤其当蚜虫在低龄若蚜时受感染后的多次脱皮,可有效地摆脱球孢白僵菌分生孢子的侵染,降低该菌的毒力。     

Entomopathogens of phlebotomine sand flies: laboratory experiments and natural infections.

The susceptibility of different geographical strains of Phlebotomus papatasi to a cytoplasmic polyhedrosis virus (CPV) was determined experimentally by feeding polyhedra to larvae. Of the Indian P. papatasi, 15.6% became infected, whereas Egyptian P. papatasi were mostly refractory. Infection rates were not augmented in colony flies from the Jordan Valley, 23.8% of which were naturally infected with CPV. The infectivity of Serratia marcescens and Beauvaria bassiana to P. papatasi were determined experimentally. A suspension of B. bassiana spores or S. marcescens bacteria, ingested by P. papatasi in sucrose solution, did not significantly augment mortality rates or reduce the number of eggs oviposited. However, B. bassiana spores smeared on a filter paper constituting 1 or 5% of the surface area available to flies induced 100% mortality of P. papatasi on days 5 and 4, respectively. Mortality in Lutzomyia longipalpis reached 100% on day 4. There were markedly lower mortality rates in the control groups and more eggs were produced by these females (P. papatasi: control = 48.5; experimental = 0.9-1.6 eggs/female; L. longipalpis; control = 17.1; experimental = 0 eggs/female). From wild-caught Colombian Lutzomyia spp., a nonfluorescent pseudomonas, an Entomophthorales fungus, and a Trypanosomatid protozoon (probably Leptomonas) were isolated in culture media. Gregarines (Ascogregarina saraviae) and nematodes (Tylenchida and Spirurida) were also recorded. In laboratory-reared flies, an ectoparasitic fungus was associated with high mortality rates of first instar Lutzomyia spp. larvae. Opportunistic ectoparasitic aggregates of bacteria, yeast, and fungi on the tarsi of colonized L. longipalpis and P. papatasi hindered their mobility and were associated with reduced colony vigor. Aspergillus flavus, B. bassiana, and S. marcescens were isolated from laboratory-bred P. papatasi adults.