Efficacy of Helicoverpa Armigera Nucleopolyhedrovirus on Soybean for Control of Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) in Arkansas Agriculture

Helicoverpa armigera nucleopolyhedrovirus (HearNPV) is a naturally occurring virus commercially produced for control of Heliothines, including Helicoverpa zea. One drawback with using this virus for control has been the slower time to mortality compared with synthetic insecticides. However, a new formulation (Heligen®) has anecdotally been thought to result in quicker mortality than previously observed. The objective of this study was to evaluate percent defoliation, the efficacy of HearNPV on mortality for each H. zea larval instar, and the potential for control of a second infestation. Fourteen days after the first infestation, all plants were re-infested with a second instar larva to simulate a second infestation. Helicoverpa armigera nucleopolyhedrovirus was effective at killing 1st–3rd instars, resulting in 99% mortality over 4–6 days. However, 4th and 5th instar mortality only reached 35%. Second infestation larvae died between 3.4 and 3.8 days, significantly faster than the 1st infestation of 2nd instars, which had a mean time to mortality of 4.9 days. An increase in mortality rate is probably due to increasing viral concentrations after viral replication within the first hosts. Final defoliation percentages were significantly smaller in the treated plants versus the untreated plants. Only 3rd and 4th instar larvae caused percent defoliation to exceed the current Arkansas action threshold of 40%. Helicoverpa armigera nucleopolyhedrovirus in the Heligen formulation can control 1st–3rd instars within 4–6 days, while keeping defoliation below the action threshold of 40%.

TmIKKε Is Required to Confer Protection Against Gram-Negative Bacteria, E. coli by the Regulation of Antimicrobial Peptide Production in the Tenebrio molitor Fat Body

The inhibitor of nuclear factor-kappa B (NF-κB) kinase (IKK) is the core regulator of the NF-κB pathway against pathogenic invasion in vertebrates or invertebrates. IKKβ, -ε and -γ have pivotal roles in the Toll and immune deficiency (IMD) pathways. In this study, a homolog of IKKε (TmIKKε) was identified from Tenebrio molitor RNA sequence database and functionally characterized for its role in regulating immune signaling pathways in insects. The TmIKKε gene is characterized by two exons and one intron comprising an open reading frame (ORF) of 2,196 bp that putatively encodes a polypeptide of 731 amino acid residues. TmIKKε contains a serine/threonine protein kinases catalytic domain. Phylogenetic analysis established the close homology of TmIKKε to Tribolium castaneum IKKε (TcIKKε) and its proximity with other IKK-related kinases. The expression of TmIKKε mRNA was elevated in the gut, integument, and hemocytes of the last-instar larva and the fat body, Malpighian tubules, and testis of 5-day-old adults. TmIKKε expression was significantly induced by Escherichia coli, Staphylococcus aureus, and Candida albicans challenge in whole larvae and tissues, such as hemocytes, gut, and fat body. The knockdown of the TmIKKε messenger RNA (mRNA) expression significantly reduced the survival of the larvae against microbial challenges. Further, we investigated the induction patterns of 14 T. molitor antimicrobial peptides (AMPs) genes in TmIKKε gene-silencing model after microbial challenges. While in hemocytes, the transcriptional regulation of most AMPs was negatively regulated in the gut and fat body tissue of T. molitor, AMPs, such as TmTenecin 1, TmTenecin 4, TmDefensin, TmColeoptericin A, TmColeoptericin B, TmAttacin 1a, and TmAttacin 2, were positively regulated in TmIKKε-silenced individuals after microbial challenge. Collectively, the results implicate TmIKKε as an important factor in antimicrobial innate immune responses in T. molitor.

The larva of Eubasilissa maclachlani White 1862 (Trichoptera: Phryganeidae) from Thailand, with notes on its biology

The final-instar larva of Eubasilissa maclachlani White 1862 is described with illustrations for the first time based on Thai specimens. The larva of E. maclachlani exhibits typical morphological characteristics of Phryganeidae. The morphological characteristics of the larva of E. maclachlani can be seen in the following features: First, the band on the frontoclypeus is anchor-like. Second, the ventral apotome is narrowly triangular. Third, the mesonotum is large and membranous, and the mesonotal sa1 sclerites are contiguous mesally. Fourth, comb-like spines, each consisting of tiny points, are distributed over much of the ventromesal surfaces of the fore- and midcoxae. Finally, the shape of tergite IX is heart-like with reddish brown dots. Larvae of E. maclachlani construct cylindrical cases made from many pieces of plant fragments, fastened together by silk in a ring-like pattern, with five successive rings. The larval habitat and phenology are also briefly discussed.

Description of the final instar larva of Anisocentropus diana Malicky & Chantaramongkol 1994 (Trichoptera: Calamoceratidae) in Thailand

The last instar larval stage of a Southeast Asian species Anisocentropus diana Malicky & Chantaramongkol 1994 (Trichoptera: Calamoceratidae) is described and illustrated based on Thai specimens. The larva of A. diana is different from known larvae of the other East Asian species A. kawamurai (Iwata) and A. magnificus (Ulmer) in its reddish-brown head without any patterns, the head’s large ventral apotome, and the abdominal gill arrangement.

The larval structures and bionomics of Idgia iriomoteana (Coleoptera: Prionoceridae)

The life cycle, bionomics and mature larval structures of the Japanese prionocerid species, Idgia iriomoteana Nakane, 1980 were investigated in captivity. The results showed that I. iriomoteana has the following characteristics: (1) the larval morph is less advanced in terms of miniaturization, and larvae pass seven larval molts before they pupate; (2) the life cycle is univoltine with summer, not winter, dormancy; (3) the first instar larvae are larger than the size of the egg, but foetomorphic larval instar (which is observed in the Melyridae: Malachiinae) is not shown. Based on comparison with melyrid species, the degree of miniaturization, dormancy behaviour, adaptation to the tropical and subtropical climates and the adaptive significance of a large first instar larva are all discussed. This study is the first to report the complete life cycle of a member of the family Prionoceridae.

Revision of the Neotropical genus Sturmiodexia Townsend, 1919 (Diptera: Tachinidae), with a new synonymy and combinations

The monotypic genus Sturmiodexia Townsend, 1919 is a poorly known Neotropical taxon. Herein a new generic synonymy is proposed for this genus: Platyrrhinodexia Townsend, 1927 syn. nov. Two new combinations are assigned for Sturmiodexia: S. moyobambensis (Townsend, 1929) comb nov. and S. punctulata (Townsend, 1927) comb nov. Redescriptions were done for S. punctulata, S. rubescens Townsend 1919 and S. muscaria (Walker 1853). With these new propositions, Sturmiodexia is left with four species. In addition, the male and female terminalia, and the first instar larva, are described and illustrated for the first time for S. punctulata. Finally, a diagnose for Sturmiodexia and a key to all species is given.

BIOLOGICAL TRAITS OF BEAN FLOWER THRIPS, Megalurothrips usitatus (THYSANOPTERA: THRIPIDAE) REARED ON MUNG BEAN

The bean flower thrips, Megalurothrips usitatus is a major pest of mung bean that causes flower dropping and significant yield loss of the crop. M. usitatus demonstrated to have variable lifespan when reared on different leguminous hosts but on mung bean, an important pulse crop in Bangladesh, is unknown. The experiment was conducted to determine the biological attributes of M. usitatus on mung bean in a climate control chamber at 26 ± 1°C, 75 ± 3% RH, and 16:8 hours L:D in the laboratory. The results revealed that the incubation period, first instar larva, second instar larva, prepupa, and pupal period of M. usitatus were 3.13 ± 0.06, 1.48 ± 0.05, 2.30 ± 0.08, 1.30 ± 0.07, and 2.26 ± 0.13 days, respectively. The combined developmental period from egg to adult was 10.54 ± 0.15 (mean ± SE) days. The larvae of M. usitatus were similar in appearance to the adults, but they lacked wings and were smaller and different in color. The first instar was pale yellow, while the second instar was darker and larger, ranging from deep yellow to orange-red. The wing pads of the prepupae were shorter than that of the pupae. The antennae of the prepupa were straight, but they were bent in the pupa. In the case of pre-adult mortality of M. usitatus, the mortality of the first instar larva was 14.41%, second instar larva 22.77%, prepupa 14.10%, and pupa 65.67%. The pre-adult mortality was 80.51% overall. Adult males had lower longevity (6.42 ± 0.44 days) than females (12.07± 1.56 days). The developmental period of M. usitatus on mung bean indicated the suitability of the leguminous crop as a potential host, as well as the need for information on the pest’s various growth stages in order to design effective management strategies.

Temperature and Photoperiodic Response of Diapause Induction in Anastatus japonicus, an Egg Parasitoid of Stink Bugs

Anastatus japonicus Ashmead is a widely used biological control agent against stink bugs that can be successfully reared using the large eggs of the Chinese silkworm. In this study, environmental factors responsible for the induction of diapause in A. japonicus were investigated on host eggs of the Chinese silkworm. A. japonicus exhibited a facultative, mature larval diapause within its host eggs. Second–third instar larva are the most sensitive stages to diapause stimuli. The accumulation of diapause stimuli during all the larval stages maximized the diapause response. A short photoperiod of 10L:14D and temperature of 17 °C led to the occurrence of the highest diapause response, while a long photoperiod (14L:10D) and low temperatures (11 and 14 °C) prevented the diapause. A specific exposure period was required to reach high diapause incidence. Diapausing mature larvae had a significantly higher survival rate after 180 days storage at 10 °C than that of nondiapausing mature larvae. Taken together, results suggest methods that could be exploited in the developmental regulation, field-release pretreatment technology, and long-term storage of A. japonicus.

EVALUATION OF CHRYSOPERLA CARNEA COMPLEX AND COCCINELLID PREDATORS AS BIOCONTROL AGENTS OF RICANIA SPECULUM (WALKER, 1851) (HEMIPTERA RICANIIDAE)

Ricania speculum is an alien insect feeding on several host plants belonging to several families, including important vegetables, crops, ornamental plants, wild plants as well as trees. For the first time, recently, Chrysoperla sp. and coccinellid beetles have been observed preying on this species in the field on Citrus sp. and Laurus nobilis plants. The main purposes of this work were to evaluate the possible predation capability of these groups of insects and determine their prey preference in laboratory trials. In the choice trials, R. speculum nymphs were paired in a confined space and exposed for 24h to single predators: Ch. carnea complex and to the coccinellids Cryptolaemus montrouzieri, Adalia bipunctata, Coccinella septempunctata, and Propylea quatuordecimpunctata. Specimens of Aphis rumicis, an aphid frequently found on her baceous plants, were used as a control prey. In the cage trials, a single Ch. carnea complex second-instar larva was placed into a jar containing a tomato plant with ten R. speculum nymphs. In the choice trials, a high mortality percentage of both preys was observed with the Ch. carnea complex, while in those with Coccinellids only high A. rumicis mortality was reported. In the cage trials, 13% mortality of R. speculm was recorded after 24h while after 72h and 168h prey mortalities reached 18% and 25%, respectively. The results of the study showed that larvae of the Ch. carnea complex could be potential predators of R. speculum, while coccinellids do not seem promising predators of this alien species.