Greater Larval Mortality Research Articles

Effects of Temperature and Photoperiod on the Immature Development in Cassida rubiginosa M\xfcll. and C. stigmatica Sffr. (Coleoptera: Chrysomelidae)

Tortoise beetles (Cassida and related genera) are a large cosmopolitan group that includes several pests of agricultural crops and natural enemies of weeds but their biology and ecology remain poorly known. Using a set of environmental chambers, we address simultaneous effects of temperature and photoperiod on immature development and adult body mass in two European species, C. rubiginosa and C. stigmatica. Consistent with its broader distribution range, the former species is less susceptible to low rearing temperatures, develops faster and has a larger body mass than the latter. However, C. rubiginosa seems to be less adapted to late-season conditions as a short-day photoperiod accelerates its immature development to a lesser extent than it does in C. stigmatica, which nevertheless results in greater larval mortality and slightly but significantly smaller adults. By contrast, in C. stigmatica, which is more likely to encounter late-season conditions due to its slower life cycle, short-day acceleration of development is achieved at no cost to survivorship and final body mass. The experiment with C. stigmatica was repeated during two consecutive years with different methods and the main results proved to be well reproducible. In addition, laboratory results for C. rubiginosa agree with field data from literature.

AcuD Gene Knockout Attenuates the Virulence of Talaromyces marneffei in a Zebrafish Model

Talaromyces marneffei is the only dimorphic species in its genus and causes a fatal systemic mycosis named talaromycosis. Our previous study indicated that knockdown of AcuD gene (encodes isocitrate lyase of glyoxylate bypass) of T. marneffei by RNA interference approach attenuated the virulence of T. marneffei, while the virulence of the AcuD knockout strains was not studied. In this study, T. marneffei-zebrafish infection model was successfully established through hindbrain microinjection with different amounts of T. marneffei yeast cells. After co-incubated at 28°C, the increasing T. marneffei inoculum doses result in greater larval mortality; and hyphae generation might be one virulence factor involved in T. marneffei-zebrafish infection. Moreover, the results demonstrated that the virulence of the ΔAcuD was significantly attenuated in this Zebrafish infection model.

Galleria Mellonella as a Model Invertebrate Host for the Study of Muriform cells of Dematiaceous Fungi

To study the pathogenesis of chromoblastomycosis using the alternative model host Galleria mellonella. We analyzed the virulence of different dematiaceous fungal strains and the host immune responses (hemocytes density and morphological changes) to Fonsecaea monophora by the alternative infection model. Then detected the development of the pathogenic muriform cells within larvae under microscope. Increasing inocula resulted in greater larval mortality and Cladophialophora carrionii was the most virulent. Low inocula activated the humoral immune response significantly. Moreover, the conidia underwent morphological transition to muriform cells within larvae. We developed an invertebrate host model that can be used to evaluate the virulence of dematiaceous fungi, which may provide further insights into overcoming current limitations in studying chromoblastomycosis in vivo.

Differential effects of offspring and maternal inbreeding on egg laying and offspring performance in the burying beetle Nicrophorus vespilloides

We investigate the effect of offspring and maternal inbreeding on maternal and offspring traits associated with early offspring fitness in the burying beetle Nicrophorus vespilloides. We conducted two experiments. In the first experiment, we manipulated maternal inbreeding only (keeping offspring outbred) by generating mothers that were outbred, moderately inbred or highly inbred. Meanwhile, in the second experiment, we manipulated offspring inbreeding only (keeping females outbred) by generating offspring that were outbred, moderately inbred or highly inbred. In both experiments, we monitored subsequent effects on breeding success (number of larvae), maternal traits (clutch size, delay until laying, laying skew, laying spread and egg size) and offspring traits (hatching success, larval survival, duration of larval development and average larval mass). Maternal inbreeding reduced breeding success, and this effect was mediated through lower hatching success and greater larval mortality. Furthermore, inbred mothers produced clutches where egg laying was less skewed towards the early part of laying than outbred females. This reduction in the skew in egg laying is beneficial for larval survival, suggesting that inbred females adjusted their laying patterns facultatively, thereby partially compensating for the detrimental effects of maternal inbreeding on offspring. Finally, we found evidence of a nonlinear effect of offspring inbreeding coefficient on number of larvae dispersing. Offspring inbreeding affected larval survival and larval development time but also unexpectedly affected maternal traits (clutch size and delay until laying), suggesting that females adjust clutch size and the delay until laying in response to being related to their mate.

Characterization of Resistance to Cephus cinctus (Hymenoptera: Cephidae) in Barley Germplasm.

Most barley cultivars have some degree of resistance to the wheat stem sawfly (WSS), Cephus cinctus Norton (Hymenoptera: Cephidae). Damage caused by WSS is currently observed in fields of barley grown in the Northern Great Plains, but the impact of WSS damage among cultivars due to genetic differences within the barley germplasm is not known. Specifically, little is known about the mechanisms underlying WSS resistance in barley. We characterized WSS resistance in a subset of the spring barley CAP (Coordinated Agricultural Project) germplasm panel containing 193 current and historically important breeding lines from six North American breeding programs. Panel lines were grown in WSS infested fields for two consecutive years. Lines were characterized for stem solidness, stem cutting, WSS infestation (antixenosis), larval mortality (antibiosis), and parasitism (indirect plant defense). Variation in resistance to WSS in barley was compared to observations made for solid-stemmed resistant and hollow-stemmed susceptible wheat lines. Results indicate that both antibiosis and antixenosis are involved in the resistance of barley to the WSS, but antibiosis seems to be more prevalent. Almost all of the barley lines had greater larval mortality than the hollow-stemmed wheat lines, and only a few barley lines had mortality as low as that observed in the solid-stemmed wheat line. Since barley lines lack solid stems, it is apparent that barley has a different form of antibiosis. Our results provide information for use of barley in rotation to control the WSS and may provide a basis for identification of new approaches for improving WSS resistance in wheat.

Toxicity of Plant Extracts toScyphophorus acupunctatus(Coleoptera: Curculionidae)

We studied the insecticidal effect of plant extracts against larvae of Scyphophorus acupunctatus Gyllenhal (Coleoptera: Curculionidae), an important pest of Agavaceae. In the bioassays, the organic extracts of Argemone mexicana L. (Ranunculales: Papaveraceae), Allium sativum L. (Asparagales: Amaryllidaceae), Bursera grandifolia (Schltdl.) Engl. (Sapindales: Burseraceae), Chenopodium ambrosioides L. (Caryophyllales: Amaranthaceae), Prosopis laevigata (Willd.) M. C. Johnst. (Fabales: Fabaceae), and Tagetes erecta L. (Asterales: Asteraceae), which were individually incorporated into artificial diet at 500 ppm, were fed to 1st instars. The variables studied were larval, pupal, and adult weight, and larval and pupal mortality. The extracts of A. sativum, A. mexicana, P. laevigata, T. erecta, and B. grandifolia reduced larval weight by at least 50%. The greatest larval mortality was caused by the extracts of A. mexicana (53%), A. sativum (43%), and T. erecta (43%), whereas the greatest mortality of pupae was caused by extracts of T. erecta. The results suggest that A. mexicana, A. sativum, and T. erecta extracts have the greatest potential for insecticidal activity against S. acupunctatus. ResumenSe estudio el efecto insecticida de extractos vegetales en contra de larvas de Scyphophorus acupunctatus Gyllenhal (Coleoptera: Curculionidae), plaga importante de Agavaceas. Se realizaron bioensayos de ingestion empleando individualmente los extractos organicos de Argemone mexicana L. (Ranunculales: Papaveraceae), Allium sativum L. (Asparagales: Amaryllidaceae), Bursera grandifolia (Schltdl.) Engl. (Sapindales: Burseraceae), Chenopodium ambrosioides L. (Caryophyllales: Amaranthaceae), Prosopis laevigata (Willd.) M. C. Johnst. (Fabales: Fabaceae) y Tagetes erecta L. (Asterales: Asteraceae), todos ellos a una concentracion de 500 ppm. Los extractos se incorporaron en una dieta artificial, sobre la cual se colocaron larvas del primer estadio del insecto. Las variables evaluadas fueron peso y mortalidad del insecto. Los extractos de A. sativum, A. mexicana, P. laevigata, T. erecta y B. grandifolia, inhibieron en un 50 por ciento el peso larval con respecto del testigo. Los extractos que provocaron mortalidad en larvas fueron: A. mexicana (53%), A. sativum (43%) y T. erecta (43%). Asi mismo, T. erecta fue la especie que produjo la mas alta mortalidad de pupas. Estos resultados permiten posicionar a A. sativum y a T. erecta como las especies mas promisorias con actividad bioinsecticida en contra de S. acupunctatus. View this article in BioOne

Galleria mellonella Larvae as an Infection Model for Penicillium marneffei.

Penicillium marneffei, the only known dimorphic and pathogenic species in the genus of Penicillium, is responsible for severe to deadly infection in immunocompromised patients. In this study, P. marneffei was able to infect the greater wax moth Galleria mellonella. The increasing inoculum doses of P. marneffei cells resulted in greater larval mortality, and the larval mortality rate also depended on the incubation temperature after P. marneffei infection and different P. marneffei strains. Moreover, the phagocytosis of hemocytes to P. marneffei was investigated, and it showed that the phagocytosis was increasing during the infection. These results demonstrated that G. mellonella can be effectively used to facilitate the in vivo study of P. marneffei infection and hemocytes are the key component of the larvae's immune defenses.

Evaluation of Galleria mellonella larvae for measuring the efficacy and pharmacokinetics of antibiotic therapies against Pseudomonas aeruginosa infection

The aim of this study was to determine whether Galleria mellonella larvae can be used (i) as an in vivo infection model for Pseudomonas aeruginosa and (ii) for evaluating the pharmacokinetics and efficacy of antipseudomonal antibiotics. Two strains of P. aeruginosa were employed, NCTC 10662 (antibiotic-susceptible) and NCTC 13437 (multidrug-resistant). Larvae were infected with increasing doses of either P. aeruginosa strain to investigate the effect of inoculum size on survival. Subsequently, infected larvae were treated with a range of antibiotics to examine whether these agents were effective against P. aeruginosa infection in vivo and whether the efficacy of these drugs matched the known susceptibilities of each bacterial strain. Larval burden of P. aeruginosa was also determined after infection and treatment with cefotaxime. Pharmacokinetic properties of the antibiotics tested were measured using a well diffusion assay to determine the concentration of antibiotics in larval haemolymph over time. Galleria mellonella larvae were sensitive to P. aeruginosa infection, and increasing inoculum doses of live cells resulted in greater larval mortality. Heat-killed bacteria had no detrimental effect on survival. Antibiotic efficacy against P. aeruginosa-infected G. mellonella correlated with the measured in vitro sensitivities of the two strains tested. The therapeutic benefit arising from administration of cefotaxime correlated with a reduced burden of bacteria present in the haemolymph. There was a clear correlation between measured antibiotic pharmacokinetics and the therapeutic effect. This study strongly supports future application of the G. mellonella infection model to initial studies of novel antipseudomonal treatments.

Insect Growth Regulatory Activity of Blechnum chilense

The genus Blechnum has 13 species that are common plants, well-distributed in Chile. Here, we report a phytochemical analysis of B. chilense (Kaulf.) Mett., as well as the insecticidal effects of extracts of this plant. From the n-hexane fraction four phytoecdysones were isolated: ecdysone, ponasterone, shidasterone and 2-deoxycrustecdysone. A bioassay with Drosophila melanogaster larvae was used to evaluate insecticidal activity. The EtOAc and n-hexane fractions at 800 ppm caused 66.7 and 50.0% larval mortality, respectively. Treatments with both extracts at 800 ppm caused the greatest larval mortality, whereas treatments with 500 and 200 ppm induced premature pupation compared with the control and the highest adult mortality, probably due to interference with ecdysteroid metabolism and inhibition of ecdysis triggering hormone (ETH). The dead adult flies exhibited malformations.

Wax moth larva (Galleria mellonella): an in vivo model for assessing the efficacy of antistaphylococcal agents

To investigate whether the wax moth larva, Galleria mellonella, is a suitable host for assessing the in vivo efficacy of antistaphylococcal agents against Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) infections. Wax moth larvae were infected with increasing doses of S. aureus to investigate the effect of inoculum size on larval survival. In addition, infected wax moth larvae were treated with daptomycin, penicillin or vancomycin to examine whether these agents were effective against S. aureus and MRSA infections in vivo. Increasing inoculum doses of live S. aureus cells resulted in greater larval mortality, but heat-killed bacteria and cell-free culture filtrates had no detrimental effects on survival. Larval mortality rate also depended on the post-inoculation incubation temperature. After larvae were infected with S. aureus, larval survival was enhanced by administering the antistaphylococcal antibiotics daptomycin or vancomycin. Larval survival increased with increasing doses of the antibiotics. Moreover, penicillin improved survival of larvae infected with a penicillin-susceptible methicillin-susceptible S. aureus (MSSA) strain, but it was ineffective at similar doses in larvae infected with MRSA (penicillin resistant). Daptomycin and vancomycin were also effective when administered to the larvae prior to infection with bacteria. This is the first report to demonstrate that antibiotics are effective in the wax moth larva model for the treatment of infections caused by Gram-positive bacteria. The new wax moth larva model is a useful preliminary model for assessing the in vivo efficacy of candidate antistaphylococcal agents before proceeding to mammalian studies, which may reduce animal experimentation and expense.

Exposure to perfluorooctane sulfonic acid (PFOS) adversely affects the life-cycle of the damselfly Enallagma cyathigerum

We evaluated whether life-time exposure to PFOS affects egg development, hatching, larval development, survival, metamorphosis and body mass of Enallagma cyathigerum (Insecta: Odonata). Eggs and larvae were exposed to five concentrations ranging from 0 to 10 000 μg/L. Our results show reduced egg hatching success, slower larval development, greater larval mortality, and decreased metamorphosis success with increasing PFOS concentration. PFOS had no effect on egg developmental time and hatching or on mass of adults. Eggs were the least sensitive stage (NOEC = 10 000 μg/L). Larval NOEC values were 1000 times smaller (10 μg/L). Successful metamorphosis was the most sensitive response trait studied (NOEC < 10 μg/L). The NOEC value suggests that E. cyathigerum is amongst the most sensitive freshwater organisms tested. NOEC for metamorphosis is less than 10-times greater than the ordinary reported environmental concentrations in freshwater, but is more than 200-times smaller than the greatest concentrations measured after accidental releases.

Management of chickpea pod borer, Helicoverpa armigera (Hubner) through Nuclear Polyhedral Virus isolates

Investigations were carried out on Helicoverpa armigera Nuclear Polyhedrosis Virus (HaNPV) isolates collected from different parts of India to study their genetic diversity through molecular characterization and their assessment in the IPM of Helicoverpa armigera on chickpea under field conditions. Variations were found in the DNA profiling of different HaNPV isolates. The similarity matrix relating the different isolates showed similarity co-efficients ranging from 0.38 to 0.82. The highest genetic similarity index of 0.82 was seen between the isolates from Raichur and Guntur followed by 0.77 between the isolates from Coimbatore and Raichur. Field evaluation of different HaNPV isolates against H. armigera in the chickpea ecosystem at the Main Agricultural Research Station, University of Agricultural Sciences, Dharwad, Karnataka for 2 years revealed that the performance of the Gulbarga and Coimbatore isolates was better than that of others in terms of their ability to cause greater larval mortality of H. armigera with a greater yield of chickpea. The Incremental Benefit Cost Ratio was highest with the Gulbarga (2.88) and Coimbatore (2.83) isolates, followed by the Dharwad isolate (2.39).

Virulence of Entomopathogenic Nematodes to &lt;I&gt;Diaprepes abbreviatus&lt;/I&gt; (Coleoptera: Curculionidae) in the Laboratory

The Diaprepes root weevil, Diaprepes abbreviatus (L.) is the most severe weevil pest in Florida citrus. Entomopathogenic nematodes have effectively suppressed larval populations of D. abbreviatus. Our objective was to conduct a broad laboratory comparison of entomopathogenic nematodes for virulence toward larvae of D. abbreviatus. The study was conducted at three temperatures (20, 24, and 29 degrees C) and included nine entomopathogenic species and 17 strains: Heterorhabditis bacteriophora Poinar (Baine, NJl, Hb, Hbl, HP88, and Lewiston strains), H. indica Poinar, Karunakar & David (original and Homl strains), H. marelatus Liu & Berry (IN and Point Reyes strains), H. megidis Poinar, Jackson & Klein (UK21l strain), H. zealandica Poinar (NZH3 strain), Steinernema riobrave Cabanillas, Poinar & Raulston (355 strain), S. carpocapsae (Weiser) (All strain), S. feltiae (Filipjev) (SN and UK76 strains), and S. glaseri (Steiner) (NJ43 strain). At 20 degrees C, the greatest mortality was caused by S. riobrave although it was not significantly greater than H. bacteriophora (Baine), H. bacteriophora (Hb), H. bacteriophora (Hbl), and H. indica (original). At 24 and 29 degrees C, S. riobrave caused greater larval mortality than other nematodes tested. Two strains of H. indica, H. bacteriophora (Baine), and S. glaseri were next in terms of virulence at 29 degrees C. Our results suggest that S. riobrave has the greatest potential for control of D. abbreviatus.

Preference-performance linkage in a herbivorous lady beetle: consequences of variability of natural enemies.

We investigated the relationship between oviposition preference and offspring performance in a herbivorous lady beetle Epilachna pustulosa on two co-occurring plant species, thistle Cirsium kamtschaticum and blue cohosh Caulophyllum robustum, in 1994 and 1995. The relative importance of bottom-up effects by host plants and top-down effects by natural enemies on offspring performance were determined using field and laboratory experiments. In both years, egg density on blue cohosh was significantly higher than on thistle. A laboratory experiment demonstrated that larval survival from hatching to adult emergence was significantly higher, and developmental period shorter when larvae were reared on blue cohosh compared to thistle. The positive preference-performance linkage varied between years in the field. Top-down effects had a different impact on larval survival on the two host plant species. Arthropod predators, a lady beetle Harmonia axyridis and an earwig Forficula mikado, considerably depressed immature survival on thistle, while they were negligible on blue cohosh. Although the lack of effective predation increased larval survival on blue cohosh, it led to defoliation due to increased larval feeding late in the season. Because of severe intraspecific competition, old larvae had significantly lower survival on blue cohosh than on thistle. In 1994, as larval survival decreased due to defoliation on blue cohosh, the overall survival rate was significantly higher on thistle than on blue cohosh. This survival pattern was opposite to that found in the laboratory experiment. In contrast, in 1995, the increase in predatory lady beetles on thistle caused greater larval mortality. Thus, the overall survival was significantly lower on thistle than on blue cohosh, although severe intraspecific competition occurred on blue cohosh as it had in 1994. Consequently, the offspring performance on the two host plants is largely determined by the relative importance of arthropod predation determining larval survival on thistle and host plant defoliation reducing late larval survival on blue cohosh. These results indicate the important role of spatial and temporal variability of natural enemies on the preference-performance linkage of herbivorous insects.

Synthesis and Biological Activity of Allosamidin and Allosamidin Analogues

The chitinase inhibitor/insect ecdysis inhibitor allosamidin and eight allosamidin analogues have been synthesised from simple carbohydrate starting materials. Allosamidin was assayed against Tineola bisselliella (Hummel) larvae and all nine compounds were examined for their effects on the development of larvae of Lucilia cuprina (Wiedemann). High larval mortality compared to controls resulted when T. bisselliella and L. cuprina larva were exposed to allosamidin. The (1→3) linked regioisomer, the dimeric analogue and the gluco-configurated dimeric analogue of allosamidin all showed high activity against L. cuprina larvae. The regioisomer, the (1→3) linked isomer and its dimeric analogue, as well as the monomer allosamizoline and its regioisomer, were inactive. These new in-vivo results are consistent with known in-vitro insect chitinase inhibition data, in that greatest larval mortality was exhibited by the best inhibitors.

The effect of a foliar disease (rust) on the development of Gastrophysa viridula (Coleoptera: Chrysomelidae)

Abstract. Gastrophysa viridula Degeer (Coleoptera: Chrysomelidae) and the pathogenic rust fungus Uromyces rumicis (Schum.) Wint. both occur on leaves of Rumex crispus L. and R.obtusifolius L. Individual stages of beetle development, and egg laying, were compared on healthy and infected leaves of each plant species in the laboratory. Oviposition choice was investigated in the field and laboratory. Beetles reared on infected leaves of each species had greater larval mortality and slower development than those reared on healthy leaves. Although larvae feeding on infected leaves consumed up to 2.5 times more dry weight than those reared on healthy leaves, they had a lower relative growth rate and pupated at a lower weight. These changes were consistent with the reduced nutritive quality of rust‐infected Rumex leaves. Fecundity of beetles reared on infected leaves of both species was considerably reduced. Eggs laid by beetles feeding on infected R.crispus leaves also had a reduced viability. The beetle developed consistently poorer on healthy R.crispus than on healthy R.obtusifolius throughout its life‐cycle. Differences in larval performance were greater between host species than between infected and healthy leaves. Oviposition was similar on infected and healthy R.crispus in both the laboratory and field. However, adults consumed less, and laid fewer eggs on infected than on healthy R.obtusifolius. The pattern of egg laying on different aged leaves was affected by rust infection: a greater proportion of eggs was laid on the older, infected leaves, than on the equivalent aged leaves on the healthy plants. Few larvae survived from eggs laid on rusted leaves in the field.

Dormant-Season Sprays Affect the Mortality of Peach Twig Borer (Lepidoptera: Gelechiidae) and Its Parasitoids

The effectiveness of a dormant-season oil spray with or without an organo-phosphate insecticide for control of the peach twig borer, Anarsia lineatella Zeller, was investigated. Results from experimental field plots indicated that an application of a dormant oil alone resulted in poor control of peach twig borer inside the hibernaculum. Limb crotches containing live peach twig borer in hibernacula were field-collected and treated in the laboratory with either organophosphate (diazinon) and oil insecticides or varying concentrations of a dormant oil alone. Significantly greater larval mortality was found in the organophosphate treatment, whereas mortality in the oil treatments was not significantly different from the control. Overwintering larvae from an insectary colony that were exposed to two rates of an oil had significantly greater mortality than larvae in a control sprayed with water, indicating that peach twig borer inside the hibernaculum may be protected from the insecticidal activity of the oil. To determine the effect of dormant sprays on parasite species composition and numbers, peach twig borer were field-collected and reared through to adult moths or parasitoids. Parasitoid activity was low, with only 0.79% of peach twig borer parasitized (n = 3,032). Macrocentrus ancylivorus Rowher, Spilochalcis n.sp. aff torvina (Cresson), Paralitomastix pyralidis (Ashmead), Erynnia tortricis (Coquillett), Euderus cushmani Crawford, and an unidentified braconid species were reared from 2,528 peach twig borer collected in orchards that did not receive an organophosphate insecticide. A single parasitoid, M. ancylivorus , was reared from 504 peach twig borer collected in orchards treated with an organophosphate insecticide. The virtual absence of peach twig borer parasitoids in fields treated with an organophosphate may be a reflection of the low number of moth pests collected at those sites.

Interspecific competition among Aedes aegypti, Ae. albopictus, and Ae. triseriatus (Diptera: Culicidae): larval development in mixed cultures.

Interactions among the larvae of Aedes aegypti (L.), Ae. albopictus (Skuse), and Ae. triseriatus (Say) were studied in trispecific and bispecific mixed populations under laboratory and field conditions. Competitive stress (as evidenced by the average time to first, 50, and 75% pupation and the total pupation periods for mixed populations of each species in comparison with their single species controls) was more pronounced in mixed cultures reared in glass jars in the laboratory than in tires under field conditions. In the laboratory, the larval development of Ae. aegypti reared together with Ae. albopictus or Ae. triseriatus, or both, larvae was accelerated significantly. Conversely, the time to pupation for Ae. albopictus and Ae. triseriatus was delayed when reared with Ae. aegypti. However, the average wing length of female Ae. albopictus and Ae. triseriatus was greater in the mixed cultures than in single species cultures. These data indicated that the effect of intraspecific competition was greater than interspecific competition. Adequate food and higher temperature appeared to promote rapid development and higher survival of the immature stages of the three Aedes species in tires placed in the field. In general, Ae. triseriatus larvae required a longer period for larval development and had greater larval mortality than either Ae. aegypti or Ae. albopictus. In mixed populations of Ae, albopictus and Ae. aegypti in the jars and food-rich tires, the periods needed to attain first, 50, and 75% cumulative pupation were not significantly different than in single species controls. We conclude that no clear-cut displacement occurred in mixed experimental populations of Ae. aegypti and Ae. albopictus.

Control of porina caterpillar (Wiseanaspp.) in pasture by the fungusMetarhizium anisopliae

Abstract Chipped wheat bait inoculated with Metarhizium anisopliae (Met.) Sor. was used to control porina caterpillar in pastures at 2 sites in North Island hill country. Caterpillars became infected after feeding on bait laid on the ground when they emerged from their subterranean burrows at night to forage. Porina populations were monitored by counting live larvae and dead, fungus-infected larvae in soil samples. Many larvae were killed by fungus in trials using 9.7-38.5 kg/ha bait (at 38.5 kg/ha 90% of larvae died from fungus infection). Greatest larval mortality was recorded when soil temperatures were high. Optimum temperature for growth of M. anisopliae was 17-20°C, and, in the laboratory, infected larvae died most rapidly at 19-25°C. M. anisopliae inoculated wheat baits show promise for controlling porina and other insects which will also accept these baits.

Comparison of Single and Combined Insecticides for Control of Tomato Pinworm in Florida12

Three replicated field experiments were conducted during 1972–73 to find insecticides or combinations of insecticides to control Keiferia lycopersicella (Walsingham) on tomato. Granular insecticides in general did not perform as well as most spray materials for reduction of tomato pinworm mines and larvae in tomato transplants. Acephate, diazinon, endosulfan, and methomyl kept seedlings nearly mine-free but greatest larval mortality was observed with azinphosmethyl, demeton, and phosalone. Chlordimeform was phytotoxic to seedlings but when sprayed alone or combined with Bacillus thuringiensis Berliner gave good pinworm control without phytotoxicity to field plants. In general, all insecticides applied as tank mixes reduced fruit loss by pinworm when compared to the check. Combinations containing acephate, leptophos, or methomyl provided superior control to combinations containing B. thuringiensis or carbaryl. No correlation was evident among leaves mined, presence of larvae, and fruit lost. Due to the larval habit of movement to new foliage and fruit, an active insecticide residue appeared essential to sustain damage free fruit.