Influence of natural and non-natural diets on the fitness and rearing of Pectinophora gossypiella Saunders.

In order to develop integrated management approaches for Pectinophora gossypiella, basic studies are crucial. The two-sex life table is the most important tool for describing the fitness and population parameters of both sexes (male and female) of an insect, while the traditional life table only explains the female sex of an insect. However, no study has reported on the biology of P. gossypiella using two-sex life table tools. Therefore, this study explains the rearing dynamics of P. gossypiella on a cotton seed-based artificial diet and a natural diet (mature cotton bolls). According to the results, the oviposition period of P. gossypiella was recorded to be longer on the artificial diet (9.07 ± 0.24) compared to the natural diet (7.40 ± 0.11). The total fecundity of P. gossypiella was greater on the artificial diet (125.94 ± 3.06) in comparison to the natural diet (60.37 ± 1.10). The population parameters, including intrinsic rate of increase, finite rate of increase, gross reproductive rate, and net reproductive rate of P. gossypiella were highest on the artificial diet in comparison to the natural diet. This study concluded that the cotton seed-based artificial diet was most suitable for the rearing of P. gossypiella. In the future, P. gossypiella may be studied in depth in light of the findings in this study.

Preference and effect of gustatory sense on sugar-feeding of fire ants.

BACKGROUND: The red imported fire ant is one of the notorious species of ants all over the world. Sugar is one of the most important components of food and necessary for the survival of ants. Because more than 70% food of fire ants is honeydew produced by Homopteran insects such as aphids and scales. METHODOLOGY: It is well known that beetles, flies, and honey bees can recognize the sugar taste through their legs and antennae, but in the case of fire ants, no records regarding gustatory sense were published. In the current study, considering the importance of sugar bait, we investigated the gustatory sense of the fire ant workers to sucrose via behavioral sequence and gustatory behavior. First, the feeding sequence (ethogram) of the fire ant workers on most preferred sugar (sucrose) solution was observed and categorized. Secondly, the gustatory behavior of treated fire ant workers (without flagellum and foreleg tarsi treated with HCL solution) was observed on the sucrose solution. In addition, using scanning electron microscopy (SEM) techniques, we identified the possible porous sensilla types on antenna flagellum and foreleg tarsi of fire ant workers. RESULTS: Based on the results of feeding sequence, foreleg tarsi of workers were the main body appendages in the detection of the sucrose droplet as compared to antennae flagellum and palps. Feeding time of treated workers with HCL solution was significantly decreased on sucrose solution as compared to those workers having no flagellum. While both types of treated workers have less feeding time in comparison to normal workers. Based on the results of feeding sequence analysis and feeding time, it is indicating that the foreleg tarsi of workers play a more important role in the detection of sucrose solution as compared to antennae flagellum. Based on the SEM results, sensilla chaetic, trichoid II, and basiconic I and II have a clear pore at their tip. This study provides a substantial basis for elucidating the gustatory function of antennal and tarsal sensilla on appendages of fire ant workers to sugars and further baits improvement for the management of fire ants.

Unraveling the Mode of Action of Cordyceps fumosorosea: Potential Biocontrol Agent against Plutella xylostella (Lepidoptera: Plutellidae).

The entomopathogenic fungus, Cordyceps fumosorosea is a potential eco-friendly biocontrol agent. The present study revealed the entire course of infection of P. xylostella by C. fumosorosea with particular reference to cuticular penetration. Comparative studies on the infection of Plutella xylostella larvae by two strains of C. fumosorosea with different pathogenicity were carried out using light, scanning, and transmission electron microscopy. We found that C. fumosorosea tended to adhere to the cuticle surfaces containing protrusions. Although conidia of the lower pathogenic strain IFCF-D58 germinated, they failed to penetrate and complete the development cycle. In contrast, the higher pathogenic strain IFCF01 began to germinate within 4 h and attached to the cuticle by a thin mucilaginous matrix within 8 h post-inoculation. After 24 h post-inoculation, germ tubes and penetrating hyphae reached the cuticular epidermis and began to enter the haemocoel. Within 36 h post-inoculation, the hyphal bodies colonized the body cavity. Hyphae penetrated from inside to outside of the body after 48 h and sporulated the cadavers. After 72 h post-inoculation, numerous conidia emerged and the mycelial covered the entire cuticular surface. The two strains showed similarities in terms of conidial size and germination rate. However, IFCF-D58 exhibited significantly fewer appressoria and longer penetrating hyphae compared to the more infective IFCF01 on all surface topographies. The current pathogen invasion sequence of events suggested that the aggressive growth and propagation along with rapid and massive in vivo production of blastospores facilitate the conidia of IFCF01 to quickly overcome the diamondback moth's defense mechanism.

Effect of constant and fluctuating temperature on the circadian foraging rhythm of the red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae).

Understanding circadian foraging rhythms activity of the red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae) foragers at different temperatures is an important step towards developing control measures in Integrated Pest Management (IPM) programs. In this study, the circadian foraging rhythm activities of S. invicta foragersat different temperature were investigated under laboratory and field conditions. Results indicated that the foraging activity increased after sunrise, and maximum foraging occurred at 14:00 (foraging rate was 69.22 ±â€¯0.57 and 72.58 ±â€¯1.15 foragers/min in the first and second year, respectively) in the tea fields of Guangzhou during autumn. Furthermore, foragers demonstrated circadian rhythms and exhibited a unimodal after 24 h. A significant correlation was found between foraging activity and temperature. S. invicta colonies were active at moderate soil temperatures (approximately 26.65 °C to 29.24 °C). The preferred temperature of the colonies was 26 °C, followed by 22 °C and 18 °C in the laboratory. The individual S. invicta activity was maximum at 17:00 (18.67 ±â€¯1.66 times /10 min) and minimum at 5:00 (8.33 ±â€¯2.51 times/10 min) at 26 °C. The fluctuating temperature had a significant impact on individual locomotor activity (r = 0.8979, P < 0.01) but did not alter the rhythm activity. Our results demonstrated that temperature might play an important role in circadian foraging rhythms activity of S. invicta. These results may have implications for the development of more effective fire ant management strategies.

Determination of fitness traits of Orius strigicollis Poppius (Hemiptera: Anthocoridae) on Pectinophora gossypiella (Lepidoptera: Gelechiidae) using two-sex life table analysis.

BACKGROUND: Pink bollworm (Pectinophora gossypiella) is a destructive insect pest of cotton crops in China and globally, which is actively predated on by Orius strigicollis. Studies on the fitness or survival of O. strigicollis fed on P. gossypiella at different temperatures have not been reported. The fitness of O. strigicollis may be well explained using two-sex life table parameters. Thus, the present study provides important insights for the effective biocontrol of P. gossypiella. METHODOLOGY: Considering the importance of fitness parameters and biocontrol, the present study explores the feeding potential and age-stage, two-sex life table traits of O. strigicollis on P. gossypiella eggs at different temperatures (24, 28 and 32 °C) in the laboratory. RESULTS: The intrinsic rate of increase (r) was higher at 28 °C (0.14 d-1) than at 24 °C (0.0052 d-1) and 32 °C (0.12 d-1). Similarly, the net reproductive rate (R 0) was higher at 28 °C (17.63 offspring) than at 24 °C (1.13 offspring) and 32 °C (10.23 offspring). This concluded that the maximum feeding potential and growth capacity of O. strigicollis could be attained at 28 °C when fed on P. gossypiella eggs. O. strigicollis adults preferred to feed on P. gossypiella eggs compared with first instar larvae. Based on these results, the present study suggests that O. strigicollis represents a promising biological control agent against P. gossypiella eggs in cotton fields.

Using a Two-Sex Life Table Tool to Calculate the Fitness of Orius strigicollis as a Predator of Pectinophora gossypiella.

A two-sex life table is a useful tool for studying the fitness of predators. Previous studies of Orius strigicollis Poppius (Heteroptera: Anthocoridae) fitness have not been done on Pectinophora gossypiella (Lepidoptera: Gelechiidae) using a two-sex life table tool. This study reports the fitness of the minute predatory flower bug, O. strigicollis when feeding on the cotton pest P. gossypiella using a two-sex life table tool. Different densities (5, 10, and 15 eggs) of P. gossypiella eggs were used to calculate the feeding capacity and fitness of O. strigicollis in the laboratory at 28 °C ± 1, 75 ± 5% RH and 16:8 (L:D). The results concluded that O. strigicollis is an efficient predator of P. gossypiella. The maximum growth capacity of the predatory bug O. strigicollis was attained when it was fed on 10 and 15 P. gossypiella eggs. Furthermore, shorter generation and development time were also observed in the case of 15 eggs of P. gossypiella. These results suggest that O. strigicollis has considerable predatory potential and prefers feeding on P. gossypiella eggs than on the first instar larvae at the fourth instar or the female stage. Although the field potential of O. strigicollis is still unknown, this study will support future investigations in terms of field applications.

Evaluating the repellent effect of four botanicals against two Bactrocera species on mangoes.

BACKGROUND: Bactrocera dorsalis and B. correcta are economically important fruit fly pests of crops, vegetables, fruits, and nuts worldwide, especially in China. Nowadays in China, B. correcta is a second notorious pest of many fruits after B. dorsalis. Different botanicals have been tested against the B. dorsalis but in the case of B. correcta, no records were published. METHODOLOGY: This study evaluated the repellency of four botanicals (Seriphidium brevifolium, Piper nigrum, Azadirachta indica and quercetin) in acetone dilutions (5%, 2.5% and 1%) against the B. dorsalis and B. correcta at the laboratory conditions (25 ± 2 °C, 60 ± 5% relative humidity, and a photoperiod of L:D 14:10 h). RESULTS: The number of visits after 24-48 h, oviposition punctures, and pupae made by both species were lower on the treated mangoes in comparison to untreated mangoes. S. brevifolium, P. nigrum, A. indica and quercetin have significantly reduced the visits, ovipositional punctures, and pupae of both species. Among botanicals, the P. nigrum was the most effective repellent against B. correcta and as well as B. dorsalis. However, the harmful effects of these botanicals against natural enemies are still unknown.

Effects of temperature on baseline susceptibility and stability of insecticide resistance against Plutella xylostella (Lepidoptera: Plutellidae) in the absence of selection pressure.

Plutella xylostella L. (Lepidoptera: Plutellidae) is an important pest causing significant losses to vegetables worldwide. Insecticides resistance in P. xylostella is a serious issue for scientists since last 30 years. However, deltamethrin and Bt Cry1Ac are commonly used insecticides against P. xylostella but studies involving development of resistance in P. xylostella against these two insecticides at different temperatures are lacking. The current study was aimed to find out the toxicity of deltamethrin and Bt Cry1Ac, and resistance development in P. xylostella. Results showed that the positive correlation between the temperature and toxicities of deltamethrin and Bt Cry1Ac. The results indicated -0.051, -0.049, -0.047, and -0.046 folds of deltamethrin resistance at 15 °C, 20 °C, 25 °C, and 30 °C temperatures, respectively from 1st to 12th generations. The toxicity of Bt Cry1Ac after 24 h was 2.2 and 4.8 folds on 1st generation at 20 °C and 25 °C temperatures, respectively compared to the toxicity recorded at 15 °C (non-overlapping of 95% confidence limits). Based on the results of this study, it is concluded that the temperature has a positive correlation with the toxicity of deltamethrin and Bt Cry1Ac against the larvae of P. xylostella. This study suggests that deltamethrin and Bt Cry1Ac can be included in the management program of P. xylostella on many vegetable crops. The baseline susceptibility data might be helpful to understand the resistance mechanisms in P. xylostella.

Fitness parameters of Plutella xylostella (L.) (Lepidoptera; Plutellidae) at four constant temperatures by using age-stage, two-sex life tables.

Different temperature zones have significant impact on the population dynamics of Plutella xylostella. Effective management of P. xylostella requires the knowledge of temperature tolerance by different life stages. In the current study, fitness parameters of diamondback moth were reported by using age-stage, two-sex life table traits at four constant temperatures (15, 20, 25 and 30 °C). The life cycle of P. xylostella was significantly longer at 15 °C. The 20 °C level of temperature was found optimal for fecundity, gross reproductive rate (51.74 offspring) and net reproductive rate (44.35 offspring per individual). The adult pre-oviposition period was statistically at par at all four level of temperatures. However, the survival was maximum at 20 °C as compared to other three temperature ranges. Based on the current study, it was concluded that temperature has a great role in population build-up of P. xylostella and effective management tactics should be applied to prevent significant damage to cabbage and other cruciferous crops when the temperature in the field is near 20 °C.

Comparative insecticidal activity of different plant materials from six common plant species against Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae).

Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) is one of the major insect pests of stored grains. Due to export legislation and zero-tolerance for live insect in trade commodities, extensive use of synthetic insecticides is in practice in order to eliminate pest infestations from the lots. Currently, the one and only acceptable chemical to be used in stored grain is phosphine but due to its excessive usage the stored grain pests are becoming resistant against it. Hence discovery of alternative compounds is much needed. In this study we have compared insecticidal efficacy of different plant materials from six commonly grown plants of Pakistan, viz. Allium sativum (Alliaceae), Zingiber officinale (Zingiberaceae), Cymbopogon citratus (Poaceae), Eucalyptus globulus (Myrtaceae), Nicotiana tabacum (Solanaceae), and Azadirachta indica (Meliaceae) against T. castaneum infesting stored wheat, rice, corn and gram pulse. Various plant parts were dried, powdered, and used as admixtures to the stored commodities in the experiments. The results have suggested that A. sativum (garlic) and Z. officinale (ginger) were more effective resulting into 15 times higher adult mortality and 4 to 5 times reduction in grain weight losses when mixed with rice grains. Similarly, A. indica when admixture with wheat checked the population growth in the resources resulting into 3.5 times less adult production compared to controls. A subsequent experiment was conducted to study the dose response of neem seed powder against the beetle pest infesting milled products. Surprisingly, better control was observed either at lowest (1% w/w) or the highest doses (5% w/w). This finding is of great interest to understand the underlying phenomenon which we assume is the ability of T. castaneum to feed selectively in flour mediums, however, further research on this aspect is required to be investigated. The results of this study support the use of botanicals for stored product pest management.

Benzenedicarboxylic acid upregulates O48814 and Q9FJQ8 for improved nutritional contents of tomato and low risk of fungal attack.

BACKGROUND: Tomato is an important food item and a cocktail of phytonutrients. In the current study, metabolites from a non-pathogenic fungal species Penicillium oxalicum have been exploited to obtain nutritionally augmented tomato fruits from the plants to better withstand against Alternaria alternata infection. RESULTS: Initially, bioactivity-guided assay and chromatographic analyses identified the bioactive metabolites of P. oxalicum [benzenedicarboxylic acid (BDA) and benzimidazole]. Then, ≥3 times elevated quantities of vitamins and other nutritional elements (protein, fat, fibers, and carbohydrates) were achieved by the foliar application of BDA. The maximum increase (625.81%) was recorded in riboflavin contents; however, thiamine showed the second highest enhancement (542.86%). Plant metabolites analysis revealed that jasmonic acid contents were boosted 121.53% to significantly enhance guaiacyl lignin defenses along with the reduction in coumarin contents. The protein profile analysis explored three most actively responding protein species toward BDA applications, (i) palmitoyltransferase protein Q9FLM3; (ii) serine/threonine-protein kinase O48814; and (iii) E3 ubiquitin-protein ligase Q9FJQ8. The O48814 improved plant defenses; whereas, Q9FJQ8 protein was negatively regulating cysteine-type endopeptidase activity and assisted plant to resist schedule alterations. Tomato cultivar with more active innate metabolism was found to be more responsive toward BDA. Furthermore, the bioactive compounds were enriched by using the two-step extraction method of ethyl acetate and chloroform, respectively. CONCLUSION: Penicillium oxalicum a non-pathogenic fungal species, produced BDA, induced nutritional contents in tomato and protected it against Alternaria alternata. The current study is the first report on the bioactivity of BDA and benzimidazole concerning the nutritional enhancement and plant defense improvement. © 2019 Society of Chemical Industry.

Using Two-Sex Life Table Traits to Assess the Fruit Preference and Fitness of Bactrocera dorsalis (Diptera: Tephritidae).

Bactrocera flies are economic pests of agricultural crops all over the world. Among Bactrocera flies, oriental fruit fly is an economically important pest of fruit crops in the world. Basic studies of Bactrocera flies are very important and helpful to the development of integrated management strategies. However, basic studies regarding behavior and age-stage, two-sex life table traits for this pest, which are vital for designing effective control methods, are currently lacking. Considering the importance of B. dorsalis, this study aimed to evaluate the fruit preference and age-stage, two-sex life table traits of B. dorsalis on guava (Psidium guajava), papaya (Carica papaya), and banana (Musa acuminata) fruits in the laboratory. In choice and no-choice tests, the number of visits and oviposition punctures made by female B. dorsalis flies were significantly higher on guava than those on papaya and banana. The life cycle from eggs to male (146.95 ± 3.43 d) and female (164.94 ± 3.85 d) adults was significantly longer on papaya than those on banana and guava. Bactrocera dorsalis females produced significantly more eggs when fed on guava (623.30 eggs female-1) than on papaya (527.80 eggs female-1) or banana (399.60 eggs female-1). Guava was the more suitable fruit for B. dorsalis, and could be used as a bait fruit to manage the B. dorsalis during the fruiting season of papaya and banana.

Biology, taxonomy, and IPM strategies of Bactrocera tau Walker and complex species (Diptera; Tephritidae) in Asia: a comprehensive review.

Bactrocera flies are the serious pests of fruit, vegetables, and nuts over the world. Bactrocera tau Walker is an economically important pest of agricultural crops. In Asia, approximately 30-40% losses of agricultural products are caused by B. tau infestation every year. In Asia, the B. tau contains a complex of sibling species that called the tau complex. However, the basic studies of B. tau and complex species are very important for integrated management. A comprehensive review of the B. tau and complex species has not been provided elsewhere. So, considering the importance of B. tau and complex species, this study provides the published information on ecology, nomenclature, identification tools, geographical distribution, potential invasion, and IPM tactics of B. tau and complex species, which would be more informative for publication facilitating related to integrated pest management (IPM) strategies of B. tau and complex species. In IPM of B. tau and complex species, the phytochemical and biological controls have not been applied successfully in Asia; there is an urgent need to study and applications of these two mentioned control techniques against the B. tau and complex species in Asia.

Environment polluting conventional chemical control compared to an environmentally friendly IPM approach for control of diamondback moth, Plutella xylostella (L.), in China: a review.

The diamondback moth, Plutella xylostella, is recognized as a widely distributed destructive insect pest of Brassica worldwide. The management of this pest is a serious issue, and an estimated annual cost of its management has reached approximately US$4 billion. Despite the fact that chemicals are a serious threat to the environment, lots of chemicals are applied for controlling various insect pests especially P. xylostella. An overreliance on chemical control has not only led to the evolution of resistance to insecticides and to a reduction of natural enemies but also has polluted various components of water, air, and soil ecosystem. In the present scenario, there is a need to implement an environmentally friendly integrated pest management (IPM) approach with new management tactics (microbial control, biological control, cultural control, mating disruption, insecticide rotation strategies, and plant resistance) for an alternative to chemical control. The IPM approach is not only economically beneficial but also reduces the environmental and health risks. The present review synthesizes published information on the insecticide resistance against P. xylostella and emphasizes on adopting an alternative environmentally friendly IPM approach for controlling P. xylostella in China.

The effect of blow flies (Diptera: Calliphoridae) on the size and weight of mangos (Mangifera indica L.).

BACKGROUND: Pollination has a great effect on the yield of fruit trees. Blow flies are considered as an effective pollinator compared to hand pollination in fruit orchards. Therefore, this study was designed to evaluate the effect of different pollination methods in mango orchards. METHODOLOGY: The impact of pollination on quantity and quality of mango yield by blow flies was estimated by using three treatments, i.e., open pollinated trees, trees were covered by a net in the presence of blow flies for pollination, and trees were covered with a net but without insects. RESULTS: The maximum number of flowers was recorded in irregular types of inflorescence, i.e., 434.80 flowers/inflorescence. Fruit setting (bud) was higher in open pollinated mango trees (i.e. 37.00/inflorescence) than enclosed pollination by blow flies (i.e. 22.34/inflorescence). The size of the mango fruit was the highest (5.06 mm) in open pollinated tree than those pollinated by blow flies (3.93 mm) and followed by without any pollinator (3.18 mm) at marble stage. We found that the maximum weight of mango fruit (201.19 g) was in open pollinated trees. DISCUSSION: The results demonstrated that blow flies can be used as effective mango pollinators along with other flies and bees. The blow flies have shown a positive impact on the quality and quantity of mango. This study will be helpful in future and also applicable at farm level to use blow flies as pollinators that are cheap and easy to rear.