Parasitoid Emergence Research Articles

Effects of four potent entomopathogenic fungal isolates on the survival and performance of Telenomus remus, an egg parasitoid of fall armyworm.

Fall armyworm (FAW), Spodoptera frugiperda is a generalist pest known to feed on more than 300 plant species, including major staple crops such as rice, maize and sorghum. Biological control of FAW using a combination of a major indigenous egg parasitoid Telenomus remus and entomopathogenic fungi was explored in this study. Metarhizium anisopliae strains (ICIPE 7, ICIPE 41, and ICIPE 78) and Beauveria bassiana ICIPE 621 which demonstrated effectiveness to combat the pest, were evaluated through direct and indirect fungal infection to assess their pathogenicity and virulence against T. remus adults, S. frugiperda eggs and their effects on T. remus parasitism rates. Metarhizium anisopliae ICIPE 7 and ICIPE 78 exhibited the highest virulence against T. remus adults with LT50 values >2 days. ICIPE 7 induced the highest T. remus mortality rate (81.40 ± 4.17%) following direct infection with dry conidia. Direct fungal infection also had a significant impact on parasitoid emergence, with the highest emergence rate recorded in the M. anisopliae ICIPE 7 treatment (42.50 ± 5.55%), compared to the control ± (83.25 ± 5.94%). In the indirect infection, the highest concentration of 1 x 109 conidia ml-1 of ICIPE 78 induced the highest mortality (100 ± 0.00%) of T. remus adults, and the highest mortality (51.25%) of FAW eggs, whereas the least FAW egg mortality (15.25%) was recorded in the lowest concentration 1 x 105 conidia ml-1 of ICIPE 41. The number of parasitoids that emerged and their sex ratios were not affected by the different fungal strain concentrations except in ICIPE 7 at high dose. This study showed that potential combination of both M. anisopliae and B. bassiana with T. remus parasitoid can effectively suppress FAW populations.

New Record of the Egg-larval Parasitoid, Chelonus formosanus Sonan of Fall Armyworm, Spodoptera frugiperda (J.E. Smith) in the Philippines

The egg-larval parasitoid on fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) have not reported in the Philippines. This paper summarizes the global biological information on two species of Chelonus and their role in the regulation of FAW. The FAW egg masses and larvae were collected in the corn plantations inside the Lipa Agricultural Research Station, Marawoy, Lipa City, Batangas. The collected egg masses and larvae were reared at the Entomology Laboratory of the Department of Agriculture-Regional Crop Protection Center IVA. The larvae of FAW were observed for the emergence of parasitoids. Two cocoons of the parasitoid from the rearing cages were obtained for species determination. Three adults from the emerged parasitoids, each male and female, were initially preserved and labeled. Color images of habitus and other morphological characters of the parasitoid were taken using a DSLR camera attached to an Olympus SZ61-60 microscope. This research found two species that emerged from FAW: Chelonus formosanus and the new record of C. semihyalinus. We also highlight the need for more research in the Philippines on exploring the diversity of indigenous natural enemies, the development of mass-rearing techniques, and their utilization to manage fall armyworms.

Prospects for Biological Control of Macadamia Felted Coccid in Hawaii with Metaphycus macadamiae Polaszek & Noyes, a New Encyrtid Wasp Native to New South Wales, Australia.

Macadamia felted coccid (MFC), Acanthococcus ironsidei (Williams) (Hemiptera: Eriococcidae), was first discovered in 2005 on the Island of Hawaii. Host plants are restricted to Macadamia species, with Macadamia integrifolia Maiden & Betche (Proteaceae) being grown in Hawaii for nut production. Approximately 6839 hectares macadamia nuts are harvested in Hawaii with an estimated farm value of USD 48.8 million (2019-2020 records). Exploration in Australia started in November 2013 for the evaluation of potential parasitoids being host specific for introduction into Hawaii. A dominant solitary endoparasitoid of MFC from New South Wales was discovered and described as Metaphycus macadamiae Polaszek & Noyes sp. n (Hymenoptera: Encyrtidae: Encyrtinae). Biology and host specificity testing were conducted at the Hawaii Department of Agriculture, Insect Containment Facility, on nine hemipteran and three lepidopteran eggs. Results indicated that M. macadamiae is host specific to MFC. There has been no evidence of parasitism or host feeding on any of the non-target insect hosts that were tested. Parasitoid emergence from the control (MFC) averaged 30.2% compared to 0% on non-target hosts. A low rate of parasitoid emergence in the laboratory (average 30.2%) and an increased rate of MFC nymphal mortality was due to adult feeding. Field parasitism reached up to 32.7% emergence in Alstonville, New South Wales, Australia. We report on the parasitoid performance in native Australia, rearing biology, host specificity testing, and the extant natural enemies associated with MFC in Hawaii. A petition to release this parasitoid for the biocontrol of MFC in Hawaii is pending. Once permitted for release, the colony will be shared with South African Mac Nut Association for their biocontrol program of this invasive pest. They will conduct their own testing before approval for release.

The hymenopterous parasitoids of the diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), on cruciferous vegetables in Delhi, India

BackgroundThe diamondback moth (DBM), Plutella xylostella (L.) (Lepidoptera: Plutellidae), is a serious and economically important pest of crucifers in Delhi, India. Larvae and pupae of the pest were collected from the cabbage, cauliflower and broccoli crops grown in vegetable fields at the farm of ICAR-Indian Agricultural Research Institute (ICAR-IARI), New Delhi-110012, from December 2021 to June 2022. The larvae and pupae of the pest were transferred to the laboratory and reared for emergence of parasitoids’ adults at 25 ± 0.5 °C and RH 70 ± 5%.ResultsFour parasitoid species were emerged, viz. Apanteles mohandasi Sumodan & Narendran 1990, Cotesia vestalis (Haliday, 1834), Diadegma insulare (Cresson, 1865) and Diadromus collaris (Gravenhorst, 1829). Among them, A. mohandasi, C. vestalis and D. collaris were reported for the first time in Delhi, whereas D. insulare (Hymenoptera: Ichneumonidae) is recorded here for the first time in India. Additionally, the first record of parasitism by A. mohandasi on P. xylostella from Delhi was established. The highest parasitism percentage was that of C. vestalis and D. collaris. Moreover, higher parasitism rate was recorded during May 2022 in organically cultivated fields. The parasitism percentage by A. mohandasi, C. vestalis, D. insulare and D. collaris was 7.5, 22.5, 12.5 and 15%, respectively. Conversely, in conventionally farmed fields, the parasitism rates were 3.57, 16.67, 10 and 13.33%, respectively.ConclusionThe use of biological control agents particularly the parasitoids in the IPM program of P. xylostella should be considered, thereby reducing reliance on insecticides and increasing the efficacy of hymenopteran parasitoids.

Impact of egg mass layers and scale thicknesses of the fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae), on the parasitic performance of Trichogrammatoidea bactrae (Hymenoptera: Trichogrammatidae)

BackgroundFall armyworm (FAW), Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), is one of the new alien destructive pests of maize and other 350 economic crops. The majority of farmers are still depended upon chemical insecticides to suppress the pest, but S. frugiperda has succeeded to develop resistance against most of the chemical families. Improving an effective environmentally-friendly approach is highly recommended. Therefore, the egg parasitoids are the best weapon for managing the FAW in the early egg stage due to the feeding behavior of their larvae. In this regard, the impact of FAW egg mass layers and scale thicknesses, as physical barriers, on the parasitic performance of the egg-parasitoid species, Trichogrammatoidea bactrae Nagaraja (Hymenoptera: Trichogrammatidae), in non-choice and choice tests was assessed. Besides, the efficacy of FAW-produced adult wasps on the next generation based on the rates of parasitism, adults' emergence, and female progeny was determined.ResultsObtained results exhibited that T. bactrae was able to parasitize all exposed FAW egg masses but with different rates related to the layers’ number and scales' thicknesses in both tests. One-layer (83.18, 78.24%) and two-layer egg masses (65.99, 76.42%) had significantly the highest parasitism rate, while three layers (42.15, 46.05%) was the least one, in both tests, respectively. All parasitoids emerged after 10–12 days with high rates (~ 88–98%) from all the tested egg masses, and the majority offspring were female-biased in both tests. Furthermore, parasitic performance in F1 progeny was similar with that recorded in parental generation in terms of parasitism rate, high parasitoid emergency (~ 87–95%), and strongly female-biased (~ 68–76%) in all the exposed egg masses.ConclusionsThe egg parasitoid, T. bactrae, could be an efficient and recommended bio-control agent against FAW as its greatest ability to overcome the layers’ number and scales’ thickness.

Parasitoids associated with ambrosia beetles in the Euwallacea fornicatus species complex (Coleoptera: Curculionidae: Scolytinae) in Taiwan

ABSTRACT Several species of ambrosia beetles in the genera Euwallacea, Xyleborus, and Xylosandrus (Coleoptera: Curculionidae: Scolytinae) are considered major pests in agriculture, forestry and urban areas. Their concealed lifestyle allows them to evade detection, and increases their chances of being introduced to non-native regions. Their reproduction is dominated by sibling mating within maternal galleries, and this behaviour makes them difficult to control. Although a handful of studies have identified natural enemies associated with ambrosia beetles, very few have done this with the goal of creating a classical biological control programme. In this study, we sought to identify hymenopteran parasitoids associated with the invasive Euwallacea fornicatus species complex. We collected branches from infested trees in a native region in Taiwan, recorded parasitoid emergence, and attempted to rear any emerging parasitoids using laboratory reared hosts and experimentally infested logs. We identified three species of parasitoid wasps that successfully parasitised beetles in the E. fornicatus species complex. These species were all new to science belonging to the genera Eucosmophorus (Braconidae), Phymastichus (Eulophidae), and Plastanoxus (Bethylidae).

Exploration of Spodoptera frugiperda natural enemies on Zea mays cultivation area

The insect pest Fall Armyworm Spodoptera frugiperda is a new invasive pest in Indonesia and potential as a major pest on maize. Maize field at two area (highlands and lowlands) were studied for natural enemies exploration of S. frugiperda in North Sumatra, namely Deli Serdang District, Langkat, Karo and Dairi. Two maize planting areas attack by S. frugiperda from each district were selected. Plants sample that showed symptoms of S. frugiperda attack were taken by taking S. frugiperda larvae (live or dead), egg groups and insect predator. All insect presence in the area was collected. The egg and larva of S. frugiperda were kept in a laboratory until the parasitoid and pathogen emergence. The result showed that the predator found were Coccinelidae, Dermaptera (Euboriellia sp) at all surveyed area, but Sycanus sp (Reduviidae) found at Langkat District and Rhynocoris sp. found at Karo and Dairi. Tachinidae parasitoid was found at Dairi District. Spodotera fugiperda larva infected by fungi was found at Deli Serdang and Langkat district.

Parasitism by Gryon aetherium (Hymenoptera: Scelionidae) on Bagrada hilaris (Hemiptera: Pentatomidae) eggs in northcentral California.

Bagrada bug, Bagrada hilaris (Burmeister) (Hemiptera: Pentatomidae), is an invasive pest of cruciferous crops. The parasitoid Gryon aetherium Talamas (Hymenoptera: Scelionidae) is a promising biological control agent for B. hilaris because it can forage in the soil where B. hilaris deposits most of its eggs. In this study, we assessed parasitism by G. aetherium on B. hilaris eggs in situ in northcentral California, including the Salinas Valley where most cruciferous crops in the United States are grown. Parasitism was documented by leaving soil-filled trays under infested plants for 7-14 days, then removing eggs and holding them for emergence of parasitoids. Gryon aetherium accounted for over 99% of emerged parasitoids, and occurred at 11 of the 12 sampled sites. Of the 17,729 and 31,759 B. hilaris eggs collected in 2021 and 2022, 1,518 (8.84%) and 2,654 (8.36%) were parasitized by G. aetherium, respectively. Parasitism rates were generally higher inland and ranged from 3.64% to 44.93% in 2021 and from 1.01% to 23.04% in 2022, and never exceeded 15% on any sample dates at several coastal sites in the Salinas Valley. Discovery efficiency (a measure of the ability of parasitoids to locate egg patches) reached 80% or higher at all but 1 site, but exploitation efficiency (a measure of the ability of parasitoids to exploit the egg patch after it has been discovered) was generally <20%, suggesting that G. aetherium can locate egg patches efficiently but is less efficient at finding eggs within patches.

Impact of different Trichogramma chilonis populations from sugarcane fields on parasitism of Corcyra cephalonica

AbstractTrichogramma chilonis Ishii (Hymenoptera: Trichogrammatidae) is the most important parasitoid of sugarcane borers in China. T. chilonis are produced from either rearing on Corcyra cephalonica (Stainton) (Hymenoptera: Galleriidae) eggs in the laboratory or at factory level and released into the field to control sugarcane borers in China. Limited reports on the efficacy of different populations of T. chilonis in the sugarcane field against C. cephalonica are available. This study reports the parasitism efficacy and functional response of different T. chilonis populations against C. cephalonica under laboratory conditions. The number of eggs parasitized by the laboratory population of T. chilonis (total 57.05 eggs) on C. cephalonica was the highest among the different populations investigated; parasitism by the Baise population was the lowest (total 21.30 eggs). The parasitoid emergence rate of T. chilonis Baise population on C. cephalonica (102.16%) was the highest among the different populations, whereas that from the C. cephalonica laboratory population was the lowest (84.73%). The sex ratio (female/male) of T. chilonis laboratory population (3.51) was significantly higher than the other three sugarcane field populations. The functional responses of T. chilonis on C. cephalonica were determined as Holling type II. The search rate of T. chilonis laboratory population (1.0392) parasitizing on the eggs of C. cephalonica was higher than other Trichogramma populations, whereas the handling time (0.00809) was shorter than that of the other populations. The results from this study indicate that the origin of the population of T. chilonis can affect its parasitic ability upon C. cephalonica; therefore, further evaluation for control efficacy of different populations of T. chilonis against sugarcane borers, especially in the field, is warranted.

Influence of host larval weight of Anastrepha ludens on production parameters and quality attributes in the mass rearing of the parasitoid Diachasmimorpha longicaudata

AbstractLarvae of Anastrepha ludens (Loew) (Diptera: Tephritidae) are non‐native hosts of the parasitoid Diachasmimorpha longicaudata (Ashmead) (Hymenoptera: Braconidae). These hosts appear to be a very good resource for the development of D. longicaudata in a wide range of larval weights. Therefore, the present study aimed to evaluate whether the larval weight of A. ludens influences the emergence and mass‐rearing parameters of D. longicaudata, including the parasitoid's adult attributes and host selection capacity. Three mean larval weights of 29, 25, and 21 mg were considered as high, medium, and low categories for the analysis. The tests included the effect of management of host larvae in the mass rearing of the parasitoids. In addition, evaluations of flight ability, survival, fecundity, and size were carried out in the adults that emerged from the larvae of the various weight categories. There was a direct relationship between host larval weight and parasitoid pupal weight, but there was no relationship with the emergence of adult parasitoids. However, a high percentage of females emerged from heavier larvae. Similarly, although adults that developed in the heaviest larval category were larger, adult quality parameters were not affected. In the evaluations of host selection, the parasitoids oviposited randomly in the larvae from the various weight categories; there was only selection if larvae of different weights were mixed. In addition, superparasitism did not differ between larval weight categories. In the evaluation of competition for hosts in cages under field conditions, larger female parasitoids that developed in the heaviest host larvae landed more frequently on infested fruit, but oviposition was similar between females of different sizes. In conclusion, the larval weight of A. ludens influenced the size of the host puparia and of adults of D. longicaudata, but the emergence and attributes of the developed adults were similar. Therefore, it can be concluded that the low larval weights of A. ludens evaluated in this study are within the range for proper development of D. longicaudata in mass rearing. This allows several options to produce hosts at a lower cost without negatively affecting the quality of parasitoid production.

Sex Ratio, Age Structure and Parasitism in Unaspis mabilis (Hemiptera: Diaspididae) in the Philippines

Lanzones scale insect (LSI) has been an important insect pest of lanzones since its first record in 2004. It causes massive defoliation on trees which eventually results to underdeveloped and sour fruits. Different lanzones-growing areas in the Philippines were surveyed for LSI along with its associated parasitoids in commercial lanzones farms located in Laguna (Los Baños,Nagcarlan and Sta. Maria), Oriental Mindoro (Villa Cerveza, Villa Cerveza, San Gabriel-Alcate), Negros (Abante-Pamplona, Poblacion - Pamplona, Lunga, Valencia, Talisay - Negros Occidental, Jawa-Valencia, Lunga-Valencia, Bongbong), Misamis Occidental (Aloran - Misamis Occidental, Calamba, Oroquieta, Sapang Dalaga, Plaridel), Camiguin (Catarman, Poblacion, Sagay, Tagdo, Mahinog), North Cotabato (Makilala, Kidapawan, and Kabacan) and Sulu (Maimbung, Patikol,Talipao). From each collection site, a total of 10 infested trees were sampled at random with leaflets (N=10) collected in four cardinal directions around canopy. Leaflets were scanned, photographed, and transported to the laboratory. Population estimates of each local population was obtained along with demographic structure viz. age structure and male-female sex ratio. The sample per tree were kept individually in customized cages for parasitoid emergence and determination of parasitization rate. Parasitoids were identified as Aphytis sp., Encarsia sp. and 2 other unidentified species. LSI population and percent parasitism in Laguna were quite high compared to North Cotabato. Results of this study will contribute to the basic knowledge needed to improve control strategy on LSI.

Effect of Ultraviolet-B Radiating Drosophila melanogaster as Host on the Quality of Trichopria drosophilae, a Pupal Parasitoid of Drosophila suzukii

The pupal parasitoid, Trichopria drosophilae Perkins (Hymenoptera: Diapriidae), is an ectoparasitoid of the genus Drosophila with great potential for application in biological control based on its excellent control efficiency for Drosophila suzukii Matsumura (Diptera: Drosophilidae), and it has has even been commercialized by biofactories. Due to its characteristics of short life cycle, large number of offspring, easy rearing, rapid reproduction, and low cost, Drosophila melanogaster (Diptera: Drosophilidae) is currently being utilized as a host to mass produce T. drosophilae. To simplify the mass rearing process and omit the separation of hosts and parasitoids, ultraviolet-B (UVB) was used as an irradiation source to irradiate D. melanogaster pupae, and the effects on T. drosophilae were studied. The results showed that UVB radiation significantly reduces host emergence and affects the duration of parasitoid development (female: F0 increased from 21.50 to 25.80, F1 from 23.10 to 26.10; male: F0 decreased from 17.00 to 14.10, F1 from 17.20 to 14.70), which has great significance for the separation of hosts and parasitoids as well as of females and males. Of the various studied conditions, UVB irradiation was ideal when the host was supplied with parasitoids for 6 h. The selection test results showed that the female-to-male ratio of emerging parasitoids in this treatment was highest at 3.47. The no-selection test resulted in the highest rates of parasitization and parasitoid emergence rate, maximized inhibition of host development, and allowed the omission of the separation step. Finally, the results of the semi-field test showed that the parasitoids bred in this treatment could search for their hosts normally and could therefore be directly applied in the biological control of Drosophila pests in the field.

Evaluation of insecticides against bean pod borer and its larval parasitoid, Tachinid fly

In the field, insecticides were applied to observe the pod borer infestation rate and the infested pods with pod borer larvae were incubated in the laboratory to investigate the emergence of parasitoid, Tachinid fly. Emamectin benzoate 5 SG, Fenitrothion 50 EC and Neemoil (Fresh) found effective to control pod borer infestation. Emamectin benzoate 5 SG and Esfenvalerate 5 EC found safe after control for parasitoids while Curtap 50 SP and Fenvalerate 20 EC found toxic. However, maximum parasitism was recorded from control (89.78%) followed by Esfenvalerate 5 EC (88.00%), Cypermethrin 10 EC (85.72%), Emamectin benzoate 5 SG (84.56%), Fenitrothion 50 EC (81.75%) and Fresh Neemoil (79.26%). So, Emamectin benzoate 5 SG, Fenitrothion 50 EC and Fresh Neemoil can be considered for successful country bean cultivation that provide least infestation by bean pod borer and reasonable parasitism of Tachinid fly parasitoid after untreated control.

Ecological aspect of the larval parasitoid Diadegma hiraii (Hymenoptera: Ichneumonidae) as a potential biological control agent of soybean pod borer Leguminivora glycinivorella (Lepidoptera: Tortricidae).

The larval parasitoid Diadegma hiraii (Kusigemati) was evaluated as a potential biological control agent of the soybean pod borer, Leguminivora glycinivorella (Matsumura). The timing of adult emergence after overwintering was ascertained, and land-use factors that enhance population density were analyzed. Host cocoons were collected and exposed to different temperatures and photoperiod regimes. Subsequently, the emergence of parasitoid was monitored. Land-use types were categorized into 4 land-use types (Poaceae, Fabaceae, Brassicaceae, and forest). Adult parasitoid emergence was dependent on temperature, but largely unaffected by photoperiod. The estimated emergence time of parasitoid was 3 months before the occurrence of the host, suggesting that the overwintered generation may lay eggs in alternate hosts. Parasitism rate was positively correlated with the area covered by Poaceae plants within a 500-m radius of the soybean field. Based on the results of the overwintering ecology and landscape analysis, D. hiraii probably completes its life cycle in the agroecosystems. The parasitoid's effectiveness as a biological control agent may be influenced by the arrangement of land-use types in the agroecosystems surrounding soybean fields. However, the pest control provided by D. hiraii is limited because of approximately 30% of parasitism rate. Consequently, a combination of this species and cultural control and/or other biological control agents is suggested for sustainable soybean cultivation.

Effects of Host and Parasitoid Ages on Parasitism Efficiency of Dirhinus giffardii (Silvestri)1 against Zeugodacus cucurbitae2

Pesticides threaten the environment and increase amounts of resistance by pests. Ecologically friendly biological control of pests is being considered in scientific and political spheres. Fruit flies cause huge economic losses to more than 81 fruit and vegetable species. They are major pests in tropical and subtropical areas. This study used pupae of melon fly, Zeugodacus cucurbitae (Coquillett), as a host and Dirhinus giffardii (Silvestri) as the parasitoid, the biological control agent. During host-parasitoid interaction at different conditions of exposure, the rate of parasitism of a host by D. giffardii differed significantly in time. Least parasitism was of 1-day-old pupae (13.41 ± 1.10) exposed for 6 hours. Greatest percentage of parasitism was to 3-day-old pupae (43.5 ± 1.12) exposed for 24 hours. Few pupae younger than 3 days old were parasitized. Parasitoid emergence rate from pupae increased from 6 hours (21.49 ± 1.46), to 12 hours (28.30 ± 2.00), and 24 hours (33.93 ± 0.66). Percentage of emergence of 3-day-old pupae was 28.40 ± 0.59 at 6 hours, 29.51 ± 0.45 at 12 hours, and 34.11 ± 0.224 at 24 hours. To maximize in vivo production of parasitoids, 5-day-old female D. giffardii should be provided pupae ≤3 days old. Results contribute to further understanding host-parasitoid interaction important for sustainable and integrated pest management practices throughout the world.

Protein Deficient Diets: Cascade Effects on a Lepidopteran Pest and Its Parasitoid Wasp

Abstract The nutritional quality of herbivorous insects’ food can not only directly affect the herbivorous insects themselves, but can also indirectly affect their parasitoids. To investigate these cascading, multi-trophic effects, we reared cabbage looper, Trichoplusia ni (Hübner) (Lepidoptera: Noctuidae), on artificial diets (8.1, 11.5, 16.75, 25.5, 34.25, and 43 g protein/liter diet) to assess how diet protein content affected the development of this common pest and its suitability as a host for the gregarious parasitoid, Cotesia vanessae (Reinhard) (Hymenoptera: Braconidae). Nonparasitized caterpillars experienced increased mortality when reared on 8.1 g protein/liter diet, and slower development and reduced pupal mass when reared on ≤16.75 g protein/liter diet. Host diet did not affect the percentage of hosts with parasitoid emergence nor the mass of individual parasitoids. However, parasitoid broods emerging from caterpillars reared on ≤25.5 g protein/liter diet were smaller and those reared on ≤16.75 g protein/liter diet exhibited prolonged development. The consequences of host diet on these latter F1 parasitoids did not affect their reproductive fitness. Caterpillars compensated for nutrient stress, induced by either low quality diet or parasitism, by increasing the amount of diet that they consumed. These collective results demonstrate the plasticity of host-parasitoid systems. Compensatory feeding allows the host caterpillar to moderate the consequences of low quality diets, which may subsequently affect the F1 parasitoids developing within the host, but not necessarily affect the F2 parasitoid generation.

Emergence Response of Telenomus podisi (Hymenoptera: Scelionidae) to Field Temperature Originated from Colonies Reared at Different Temperature Regimes.

We studied the impact of field temperature on the emergence of Telenomus podisi Ashmead (Hymenoptera: Scelionidae) after being released as either protected (encapsulated) or unprotected pupae close to adult emergence. Two independent bioassays (protected pupae vs. unprotected pupae) were carried out in a randomized block experimental design in a 2 (parasitoid rearing temperature regimes) ×4 (release positions within plant canopy) factorial scheme. One of the T. podisi colonies was reared at a constant temperature (25°C) and 12:12h L:D (Light: Dark) photoperiod. The second T. podisi colony was reared at fluctuating temperatures (20°C during 12h D and 30°C during 12h of L). Each bioassay had five replicates. Each replicate contained 40 pupae from each rearing temperature and release position within plant canopy. Parasitoid pupae were released in the bottom third, middle third, or upper third of the plant's canopy, as well as between planting lines. Each bioassay was repeated six times (in different plant developmental stages: R1, R2, R3, R4, R5 and R6). There was no difference in emergence of parasitoids between colonies reared at different temperatures after exposure to field conditions. Emergence of T. podisi was reduced after pupae exposure to temperatures above 35°C in the field, regardless of the rearing temperature. Telenomus podisi tolerates temperature fluctuations for emergence as long as they fit the optimal range (20 to 30°C).

Primeiro relato de Cerchysiella insularis (Howard, 1897) (Hymenoptera: Encyrtidae) parasitando Lobiopainsularis (Castelnau, 1840) (Coleoptera: Nitidulidae) em morangueiro

ABSTRACT: Strawberry is one of the most socially and economically important small fruits in Brazil, with strong demand by the food industry driving high levels of production. However, phytosanitary problems, especially insect damage, can hamper strawberry cultivation. A pest of great concern is the strawberry sap beetle, Lobiopa insularis (Coleoptera: Nitidulidae), which damages the fruits. Chemical control has not been effective against L. insularis, as it makes harvesting and marketing the product unfeasible. Parasitoids have been effectively utilized to control various strawberry pests and support sustainable production. We report the occurrence of the wasp Cerchysiella insularis (Hymenoptera: Encyrtidae) as a parasite of L. insularis on strawberries in São José dos Pinhais, Paraná, Brazil. Samples of strawberries (San Andreas cultivar) attacked by L. insularis were collected from February to March, 2019. Lobiopa insularis larvae were individually placed in rearing pots, fed on San Andreas strawberries, and checked weekly for symptoms of parasitism or parasitoid emergence. Parasitism rates were 33.85% in March and 45.90% in February. The sex ratio varied between 0.88 and 0.86. All parasitized larvae were infested by C. insularis. The natural parasitism rate above 33% and high sex ratio of C. insularis in strawberry crops indicated that it may have the potential in the control of L. insularis.

Efficiency of the Egg Parasitoid Trichogramma evanescens for the Control of Potato Tuber Moth, Phthorimaea operculella under Laboratory Conditions

Mohamed, H.Z., S.M. Ali and H.M. Khodair. 2023. Efficiency of the Egg Parasitoid Trichogramma evanescens for the Control of Potato Tuber Moth, Phthorimaea operculella under Laboratory Conditions. Arab Journal of Plant Protection, 41(4): 391-397. https://doi.org/10.22268/AJPP-41.4.391397 The efficiency of the egg parasitoid Trichogramma evanescensin controlling the eggs of the potato tuber moth, Phthorimaea operculella, was evaluated at two temperatures 20 and 25ºC and using different ages of host eggs in the laboratory. The temperature of 25˚C was the best for the period required for blackening of the host's eggs, parasitism efficiency and adult’s emergence rate. The results also showed the use the 396 مجلة وقاية النبات العربية، مجلد ،41 عدد 4 ) 2023( host's eggs age of 24, 48 and 72 hours led to a parasitism rate of 83.33, 68.33 and 58.33%, respectively, at temperature of 25ºC. The results also showed the importance of the age of the host eggs age in determining the parasitoid emergence rate, which reached 75.9% when 24 hours old eggs were used. Results obtained indicated that the parasitoid Trichogramma evanescens can be used as a biological control agent of the potato tuber moth. Keywords: Trichogramma evanescens, Phthorimaea operculella, biological control

The Association between the Distribution of Resin Beads and the Emergence of Sirex noctilio on Red Pine in North America.

This study examined the relationships of the abundance and distribution of resin beads (signs of Sirex noctilio parent female ovipositor activity) with the abundance and distribution of emerging progeny of S. noctilio, S. nigricornis and their parasitoid Ibalia&amp;nbsp;leucospoides. S. noctilio is native to Europe and is an invasive pest of pines in the Southern Hemisphere and North America; S. nigricornis is native to North America and is a secondary pest of dying pines. I.&amp;nbsp;leucospoides is a parasitoid that has been widely deployed for biological control of S. noctilio. This study aimed to determine if the distribution of resin beads is associated with the height, diameter, or cardinal direction on red pines, Pinus resinosa, as well as the distribution of wood wasp and parasitoid emergence. Our results showed that among log sections taken at five heights, resin beads were most abundant on the north, east, and south sides of logs and mid log at 4.5 m above the ground. Emergence of S. noctilio was most abundant only from logs with more than five resin beads per square meter, while diameter and height were not contributing factor. None of variables evaluated (resin bead densities, height, and diameter) had significant effects on the emergence of S. nigricornis and I. leucospoides. These findings help clarify the biological significance of resin beads as indicators of S. noctilio colonization of host trees in North America.