Flight and Reproduction Variations of Rice Leaf Roller, Cnaphalocrocis medinalis in Response to Different Rearing Temperatures

Understanding how species that follow different life-history strategies respond to stressful temperature can be essential for efficient treatments of agricultural pests. Here, we focused on how the development, reproduction, flight, and reproductive consequences of migration of Cnaphalocrocis medinalis were influenced by exposure to different rearing temperatures in the immature stage. We found that the immature rice leaf roller that were reared at low temperatures (18 and 22 °C) developed more slowly than the normal temperature 26 °C, while those reared at high temperatures (34 °C) grew faster. Female adults from low immature stage rearing temperatures showed stronger reproductive ability than those at 26 and 34 °C, such as the preoviposition period (POP) significantly decreased, while the total lifetime fecundity obviously increased. However, 34 °C did not significantly reduce the reproductive performances of females compared to 26 °C. On the contrary, one relative decreased tendency of flight capacity was found in the lower immature temperature treatments. Furthermore, flight is a costly strategy for reproduction output to compete for limited internal resources. In the lower temperature treatments, after d1-tethered flight treatment, negative reproductive consequences were found that flight significantly decreased the lifetime fecundity and mating frequency of females from low rearing temperatures in the immature stage compared to the controls (no tethered-flight). However, in the 26 and 34 °C treatments, the same flight treatment induced a positive influence on reproduction, which significantly reduced the POP and period of first oviposition (PFO). The results suggest that the experience of relative high temperatures in the immature stage is more likely to trigger the onset of migration, but lower temperatures in the immature stage may induce adults to have a greater resident propensity with stronger reproductive ability.

Development of weather based prediction model for leaf roller population of Sesame in Bundelkhand zone of Madhya Pradesh

Field experiment was conducted during twelve consecutive Kharif seasons from 1995 to 2006 at Zonal Agricultural Research Station, Tikamgarh to find out the impact of weather parameters on the incidence and activity of Antigastra catalaunalis (Dupnocbel) in Sesame cv JT-7. The analysis revealed that the pest activity started to buildup from 30th standard meteorological week and remained up to 40th standard meteorological weeks (SMW). Larval population has been correlated with weather data and correlation coefficient, regression equations were worked out for development of weather based prediction model. Significant positive correlation with maximum and mean temperature (maximum, minimum) and negative relationships with rainfall was observed. Best fitted polynomial models were developed using the whole season data which explained 60 to 90 per cent variability due to weather parameters. The multiple regression technique has been used for developing predictive model using larval population and weather data not only for the corresponding week but also for preceding weeks. The prediction model for leaf roller explained 88% variability of the pest population. The model predicted peak larval population was in good agreement with observed peak larval population.

The genome sequence of the hazel leaf-roller, Apoderus coryli (Linnaeus, 1758)

We present a genome assembly from an individual male Apoderus coryli (the hazel leaf roller; Arthropoda; Insecta; Coleoptera; Attelabidae). The genome sequence is 428 megabases in span. The majority (98.90%) of the assembly is scaffolded into 20 chromosomal pseudomolecules, with the X and Y sex chromosomes assembled.

Efficacy of Beauveria bassiana against the cotton leaf roller, Haritalodes (Syllepte) derogata (Fabricius, 1775) (Lepidoptera: Crambidae) under laboratory conditions.

Objective: The leaf-roller caterpillar Haritalodes (=Syllepte) derogata (Fabricius, 1775) (Lepidoptera: Crambidae) induces high yield losses by damaging cotton leaves and reducing the photosynthetic activity of the plant. Laboratory bioassays were carried to evaluate the effect of Beauveria bassiana on the survival of H. derogata larvae. Methodology and results: In the first trial, screening of thirteen B. bassiana isolates was performed on third larval instars at 107 conidia.mL-1 . In the second trial, effects of five concentrations (105 to 109 conidia.mL-1 ) of the three best isolates of the fungus were tested. Conidia suspension was applied on each larva topically. Germination rates of conidia used varied between 90.2% to 95.7%, 24 hours after incubation. Five isolates were found to be the most promising namely Bb116, Bb3, Bb11, Bb6 and Bb115. In the second bioassay, caterpillar mortality increased with fungal concentration. Lethal Concentration (LC50) was estimated to 1.18x1015 conidia.mL-1 , 1.75x1013 conidia.mL-1 , 1.75x1013 conidia.mL-1 , 9 days after inoculation for Bb3, Bb11 and Bb115, respectively. Conclusion and application of results: The use of B. bassiana as a biopesticide against H. derogata could be a good alternative method to control the pest. It is an environmentally friendly method with less side effects compared to the application of synthetic pesticides on cotton. This method could be tested in future station and field experiments. Keywords: Cotton, Integrated pest management, Haritalodes (=Syllepte) derogata, Beauveria bassiana, Lethal Concentration.

Incidence of banana leaf roller and diversity of it is parasitoids in Central Sulawesi, Indonesia

Pasaru F, Yunus M, Toana MH, Edy N, Anshary A, Saleh S. 2021. Incidence of banana leaf roller and diversity of it is parasitoids in Central Sulawesi, Indonesia. Biodiversitas 22: 5023-5029. Incidence of banana leaf roller and diversity of it is parasitoids in Central Sulawesi, Indonesia. Indonesia is still facing banana losses due to the leaf roller (Erionota thrax). Fortunately, it has several natural enemies potentially to control them. Therefore, a survey was done to measure the incidence of banana leaf roller (BLR) at different altitudes and banana cultivars as well as the diversity and parasitism of its parasitoids. The pra-imago stages of BLR were collected at different altitudes and banana cultivars in Central Sulawesi, Indonesia, and transported to the laboratory for rearing and parasitism observation. The study revealed that the incidence of E. thrax in the surveyed locations varied from 28.6% to 85.8%, whereas the parasitism level of the BLR parasitoids was 0.0 to 22.1%. Incidence of E. thrax tended to be higher at a higher altitude while Kepok cultivar seemed to be less prone to BLR infestation compared with Raja and Mas cultivars. A total of nine parasitoids of BLR were recorded. They were Agiommatus sumatraensis, Pediobius erionotae, Ooencyrtus pallidipes, Brachymeria lasus, Brachymeria thracis, Cotesia erionatae, Xanthopimpla gampsura, Casinaria sp, and Palexorista solennis. Among them, B. lasus was the most abundant, widely distributed, and had the highest parasitism rate. Our study figured out that BLR infestation is a major problem in Central Sulawesi. Nevertheless, the presence of parasitoids recorded in this study may potentially be used as the biological control.

Adaptive strategies of Rice Leaf Roller, Cnaphalocrocis medinalis in Response to Different Rearing Temperatures

Understanding how species that follow different life-history strategies respond to stressful temperature can be essential to efficient treatments against agricultural pests. Here we focus on how the development and reproduction of C. medinalis is influenced by exposure to different rearing temperatures in the immature stage. We found that low (18 or 22 °C) or high (30 and 34 °C) rearing temperatures negatively affected the immature development and flight performance compared to the normal temperature 26 °C, with higher larval and pupal mortality, lower pupation and eclosion rates and shorter flight duration and distance. Low rearing temperatures significantly slowed down the immature process, but accelerated adult reproduction. However, high rearing temperatures had the opposite impacts. Interestingly, the flight of adults with un-mature rearing low temperatures (18 and 22 °C) significantly decreased their lifetime fecundity and mating frequency, but increased pre-oviposition period of females compared to the control; On contrast, high rearing temperatures (30 and 34 °C) significantly accelerated onset of oviposition and enhanced synchrony of spawning. These results indicate high rearing temperatures in the immature stage are more likely to trigger the onset of migration, but low rearing temperatures induces adults to have a greater resident propensity with stronger reproductive ability.

Ectoparasite Habrobracon Hebetor Say Is an Efficient Biological Control Agent of Lepidopteran Pests

Ectoparasite Habrobracon hebetor Say is one of the most widely used biological controllers in biological plant protection against a number of harmful lepidopterans, including especially dangerous pests of corn, soy, fruit and vegetable crops. As a result of research conducted in 2017, food specialization and parasitic activity of three different populations of H.hebetor were studied. Two races have been identified for mass rearing and application: pyralid and leaf roller (against corn moth, bean pod borer, apple and plum moths), and pyralid owl-moth (against cotton moth, corn borer, bean pod borer and boxwood moth). As a result of studies of biological features and trophic needs, it has been determined that caterpillars of mill moth (Ephestia cuhniellia Zella) should be used as a host insect for laboratory cultivation of the stock population of the Habrobracon pyralid and leaf roller race (race No. 1). For the introduced from South Kazakhstan the H.hebetor pyralid and noctuid race the most productive rearing is on the caterpillars of large bee moth (Galleria mellonela L.). Optimal temperature for rearing of both races is 26-28 ° C, relative air humidity is 70% and photoperiod is not less than 16 hours. It has been noticed that before laying eggs on the host’s caterpillars, the Habrobracon female preliminarily paralyzes the victim, piercing the sheath with ovipositor. As a result, the caterpillar stops eating and is immobilized. In 3-4 days larvae hatch out of the laid on the caterpillar eggs. The larvae feed on the contents of the caterpillars for 4-5 days, then pupate and after 6-8 days an adult insect leaves the cocoon. The development of one generation lasts 13-16 days, one cocoon includes one parasite. 1,000 large bee moth caterpillars used for infection provide on average 5.8-6.0 thousand cocoons, of which an average of 4.5-4.7 thousand parasites fly out.