Secondary Pests Research Articles

Diplodia twig canker (Diplodia gallae) of northern red oak (Quercus rubra) in the northeastern United States

AbstractThe 2015–2018 outbreak of spongy moth (Lymantria dispar) in southern New England initiated a severe oak decline and mortality event. While defoliation was a primary driver, increased secondary pest and pathogen activity contributed to decline and death. Following this large defoliation event, Diplodia was frequently recovered from northern red oaks (Quercus rubra) with serious outbreaks of twig cankering. Given the many recent reports of Diplodia corticola on oak in eastern North America, it was presumed to be the causal agent. To confirm, a limited survey was conducted from five states in the region (Maine, Massachusetts, New Hampshire, New York, and Vermont). Based on ITS, tef1 and tub2 sequences generated from 28 isolates collected primarily from northern red oak, Diplodia gallae, two potentially novel Diplodia species and Diplodia sapinea were identified. Surprisingly, D. corticola was not found in this study. ITS sequences alone failed to discriminate among isolates of D. gallae and D. corticola, creating uncertainty over previous reports of D. corticola in eastern North America. Only a combined ITS + tef1 dataset successfully distinguished D. gallae and D. corticola along with two other closely related species that also occur on oak (Diplodia quercicola and Diplodia quercivora). Additional cankering and endophytic fungi (Coryneum, Dendrostoma, Gnomoniopsis, Pestalotiopsis and Tubakia) were also found on symptomatic oaks in the region. Identification of Diplodia isolates from non‐Quercus hosts also detected Diplodia neojuniperi on Juniperus chinensis and Microbiota decussata, which has not been reported previously in North America.

Do Pesticide Retailers’ Recommendations Aggravate Pesticide Overuse? Evidence from Rural China

In rural China, pesticide retailers are often accused of recommending farmers apply more pesticides than the scientifically recommended rate, while playing an important role in providing technical information regarding pesticide use to farmers. However, there is little empirical evidence on the relationship between pesticide retailers’ recommendations and farmers’ pesticide overuse. Using survey data from 1084 rice farmers in four provinces, this study utilized an endogenous switching probit model to examine the impact of pesticide retailers’ recommendations on the overuse of pesticides at the level of pest-control observation, accounting for potential self-selectivity bias. Results show that the proportion of pesticide overuse at the level of pest-control observation for controlling major pests, secondary pests, and weeds is 58.5, 55, and 40.6%, respectively. Pesticide retailers’ recommendations are found to increase the probability of pesticide overuse at the level of pest-control observation for controlling major pests, secondary pests, and weeds by 62.1, 59.3, and 58.3%, respectively. The robustness check using a conditional mixed process model provided consistent findings. Accordingly, this study proposes that more efforts should be made to provide additional technology training activities for pesticide retailers, strengthen regulations on pesticide retailers’ information recommendations, and further improve socialized agricultural technology services.

Impact of Pesticides on Beneficial Insects in Various Agroecosystem: A Review

Beneficial insects play a vital role in natural pest control and pollination in agricultural crops. The use of synthetic pesticides in agricultural areas is harmful to both natural enemies and pollinators. Pesticides impair the survival of a variety of life cycle stages, limit reproductive capability, alter host fitness for parasitising or predation, reduce parasitoids' emergence from sprayed host eggs, and cause direct death. When natural enemies are decreased, pest population dynamics, such as resurgence and secondary pest eruption, may suffer even more devastating repercussions. Pollinator decline decreases agricultural yield. This study intends to investigate the side effects of synthetic and botanical pesticides on beneficial insects in order to provide a foundation for future research into the detrimental effects of synthetic and botanical pesticides on these insects. This information will aid in optimising pesticide use in integrated pest management programmes by implementing more sustainable and environment friendly methods such as the use of correct doses and selective insecticides in agricultural areas.

Updating integrated mite management fifty years later: comparing laboratory pesticide susceptibility of a "new" generalist predatory mite to a cornerstone specialist predator.

Historically, integrated mite management in Washington apple orchards has focused on the conservation of the predatory mite Galendromus occidentalis (Nesbitt) to reduce secondary pest mite pressure. However, pesticide use has changed to include more selective products, coinciding with a shift in the predatory mite community composition to include a new major predator, Amblydromella caudiglans (Schuster). There is evidence that A. caudiglans is more pesticide sensitive than G. occidentalis. Therefore, updates on pesticide selectivity recommendations are needed to conserve this "new" key predator. Using bioassays, we examined lethal (female mortality) and sublethal effects (fecundity, egg hatch, larval survival) of four fungicides and 11 insecticides on A. caudiglans, to determine if existing conservation recommendations can be applied to this predatory mite. Susceptibility was compared to prior research on G. occidentalis. Mancozeb was the least selective fungicide tested on A. caudiglans; it caused high acute toxicity and sublethal effects. Carbaryl was the least selective insecticide and caused 100% mortality. Captan was the most selective fungicide. Chlorantraniliprole and cyantraniliprole were the most selective insecticides and therefore least likely to disrupt biological control by A. caudiglans. Non-target effects on A. caudiglans and G. occidentalis were similar, but A. caudiglans experienced higher mortality to some broad-spectrum insecticides. All products tested had some non-target effects on A. caudiglans. However, A. caudiglans sensitivity to most tested pesticides was similar to G. occidentalis. In general, existing spray recommendations for conserving G. occidentalis can be adjusted slightly and applied to A. caudiglans conservation. This article is protected by copyright. All rights reserved.

Endogenous like sequence Rice Tungro Bacilliform Virus (RTBV) fragments in the local rice genome and its role in controlling tungro disease

Tungro disease is one of the important diseases in rice plants because it can cause a large decrease in production. Therefore, tungro disease needs to be controlled in wise ways that ensure environmental sustainability. This can be done by using resistant varieties, while also preventing rice from resistance to the green leafhopper vector Nepothettix virescens, the death of natural enemies, resurgence and emergence of secondary pests which become the main pests. The territory of Indonesia has many very diverse rice germ plasm which its resistance properties can be used to control tungro disease. Resistance genes are an effective control machine especially when combined with other control strategies. One of the triggers for the resistance of rice varieties is eRTBV, which is a group of RTBV nucleotides in rice DNA. The purpose of this study was to detect the presence of the eRTBV piece in the rice genome and its role in controlling tungro disease. The method used wasthe insilico method by comparing the eRTBV found in local rice varieties with that found in Genbank. The results indicated that endogenous RTBV was joined into the rice genome at 1200 bp using the primer eRTBV-7. Nucleotide blast results showed that the similarity of endogenous Indonesian local rice RTBV to endogenous RTBV in the genbank ranged between 95% and 99%, then protein blast results showed that the eRTBV fragment of local rice varieties contained ORF 3 RTBV protein with a range of similarity to the genbank of 66.9% and 93.35%. The role of eRTBV is to produce the Isoleucine protein motif which produces a physical, chemical and biochemical resistance system capable of inhibiting the green leafhopper virus vector (Nepothettix virescens) and the growth and development of tungro disease, RTBV.

Siirt İli Buğday Ekiliş Alanlarında Zararlı Eurygaster integriceps Puton (Hemiptera: Scutelleridae)’in Dağılımı İle Zararlı ve Faydalı Böcek Türlerinin Belirlenmesi

Wheat is nowadays the most important source of food on earth. Many pest species have been identified that affecting the wheat yield and quality negatively. This study was carried out to identify harmful and beneficial insect (predator) species and of distribution of Sunn pest in wheat cultivation areas in the districts (Siirt province Merkez, Kurtalan, Eruh, Tillo, Şirvan, Pervari and Baykan) of Siirt Province, Turkey in 2018 and 2019. Samplings were taken periodically 1-2 week from April to July. The sweep nets, frame, pitfall trap and visual control methods were used for sampling. At the end of the study, 31 species belonging to 5 orders and 18 families were determined. The distributions of the species were recorded as 16 species belonging to 7 families in Coleoptera, 10 species belonging to 7 families in Hemiptera, and 1 species belonging to each family in Hymenoptera, Orthoptera, Neuroptera and Diptera. The most common and abundant species: The main pest Eurygaster integriceps Puton, 1881, the secondary pests Aelia acuminata (Linnaeus, 1758), Dolycoris baccarum (Linnaeus, 1758) from Hemiptera, Cephus pygmaeus (Linnaeus, 1767) from Hymenoptera Gryllus bimaculatus De Geer, 1773, from Orthoptera were determined. Carpocoris pudicus (Poda, 1761) and Carpocoris fuscispinus (Boheman, 1850) species are the first records for the fauna of Siirt province. Furthermore, Clanoptilus geniculatus (Germar, 1823) and Haplomalachius flabellatus (Frivaldzsky, 1835), Coleoptera (Malachiidae) Libelloides macaronius (Scopoli, 1763) Neuroptera (Ascalaphidae) species are the first records for Siirt province. The highest average density of Eurygaster integriceps (2 adult+nymph / m2) was found in the Garzan and Gozpinari locations of Kurtalan district. Besides, among the beneficial species, general predators Chrysoperla carnea (Stephens, 1836) and Coccinella septempunctata (Linnaeus, 1758) are remark as the most common and abundant species.

Efficacy of different doses of phosphine against Tribolium castaneum (Herbst.) in stored rice

Rice is an important and staple cereal food in India after wheat. When rice grains are stored under bulk conditions and larger quantities, it is being damaged by several insect pests. Among different insects infesting stored rice grains, the red flour beetle, Tribolium castaneum cause significant damage as secondary storage pest. Studies were conducted on the efficacy of two different doses of phosphine such as 2 gram per MT and 3 gram per MT (metric tonne) in food grain warehouse. The results revealed that the highest concentration of phosphine was recorded on the 3rd day of fumigation and concentrations were decreased thereafter in both the dosages. It was observed that that the lower dosage 2 gram per MT was also effectively killed the adults of T. castaneum significantly as that of 3 gram per MT dosage and there were no post fumigation emergence of the pest in bioassay samples in both the dosages. By following proper fumigation procedure especially complete sealing of enclosure, the existing dosage of 3 gram per MT will work effectively in killing the stored pests in large food grain warehouses.

Determination of Harmful Insect Species in Zivzik Pomegranate Production Areas of Siirt Province

Zivzik pomegranate is an important source of income for producers in Siirt province. There are many harmful insect species that cause loss of yield and quality in pomegranate. This study was carried out to determine the pest insect species in Zivzik pomegranate production areas in Siirt province and its districts in 2018 and 2019. The study was conducted total in 38 orchards in 12 villages in 3 districts (Central, Şirvan and Pervari). To determine the insect species, samples were collected with pheromone trap, shoot cutting, visual inspection, Japanese umbrella and cultivation methods. As a result of the studies, a total of 24 harmful insect species belonging to 7 orders and 19 families were identified. Among these species, Carob moth (Ectomyelois ceratoniae (Zeller, 1839)), Pomegranate aphid (Aphis punicae Passerini, 1863) and Chrysobothris affinis (Fabricius, 1794) were found to be important species. dried fruit beetle (Carpophilus spp.) fruit fly (Drosophila melanogaster Meigen, 1830), Ash whitefly (Siphoninus phillyreae (Haliday, 1835)), leopard moth borer (Zeuzera pyrina Linnaeus, 1761) and Tenuipalpus granati Sayed, 1946 were determined as secondary pests. Furthermore, Chrysobothris affinis (Fabricius, 1794) detected in this study is the first record for the pomegranate fauna of Turkey

Tingkat Serangan Hama dan Penyakit pada Tanaman Hortikultura di Kabupaten Bangka, Provinsi Kepulauan Bangka Belitung

Pesticides are chemical ingredient used to eradicate and prevent disturbances of insects, rodents, nematodes, fungi, weeds, viruses, bacteria, and micro-organisms which are considered as harmful pests. Excessive use of pesticides can cause pest resistance, pest resurgence, emergence of secondary pests, and environmental pollution. This research aims to evaluate the use of pesticides by farmers in controlling pests and plant diseases of horticultural crops in Bangka Regency, Bangka Belitung Islands Province. This research was conducted using interview method followed by direct observations in the interviewed farmers’ fields. The results obtained from interviews and observations indicated that farmers still use synthetic pesticides unwisely in controlling pests and plant diseases of cultivated plants. Farmers still rely on their personal experience of using pesticides rather than science. Most of farmers did not understand the use of pesticides properly and correctly, so they do not understand the economic threshold for using pesticides. In conclusion, farmers still think that the more types of pesticides used, the faster the control of pests and diseases show good results. Thus, it is necessary to give extension to farmers about the use of pesticides, so that farmers can understand how to use pesticides wisely and precisely in the future. Pest and disease species that attack horticultural crops are 13 pest species and 11 disease species.

Attraction, mobility, and preference by Lasioderma serricorne (Coleoptera: Ptinidae) to microbially-mediated volatile emissions by two species of fungi in stored grain

Insects and microbes are known to interact in a variety of ways at food facilities, compounding damage. However, little research has explicated how specific common fungal species affect the behavior of the cosmopolitan secondary stored product pest, Lasioderma serricorne. Enhanced knowledge about attraction to microbially-produced volatile organic compounds (MVOCs) may be used to manipulate insect behavior. Aspergillus flavus and Fusarium verticillioides are two common, widespread pre- and postharvest fungi on small cereals that produce aflatoxins and fumonisins, respectively, while directly competing with each other for nutrients. Our goals were to (1) characterize the volatile emissions from grain inoculated by A. flavus or F. verticillioides derived from the cuticle of L. serricorne compared to uninoculated and sanitized grain, and (2) understand how MVOCs from each fungal species affects mobility, attraction, and preference by L. serricorne. Headspace collection revealed that the F. verticillioides- and A. flavus-inoculated grain produced significantly different volatiles compared to sanitized grain or the positive control. Changes in MVOC emissions affected close-range foraging during an Ethovision movement assay, with a greater frequency of entering and spending time in a small zone with kernels inoculated with A. flavus compared to other treatments. In the release-recapture assay, MVOCs were found to be attractive to L. serricorne at longer distances in commercial pitfall traps. There was no preference shown among semiochemical stimuli in a still-air, four-way olfactometer. Overall, our study suggests that MVOCs are important for close- and long-range orientation of L. serricorne during foraging, and that MVOCs may have the potential for inclusion in behaviorally-based tactics for this species.

Red flour beetle, Tribolium castaneum (Herbst): biology and management

According to an estimate, the world’s population will reach upto 9.1 billion till 2050 and food production is projected to increase up to 70%. Developing countries already facing food scarcity contribute most in population growth. In these countries, one in every six children suffers from hunger and malnutrition. In these critical situation, protection of the grains and food products from insect infestation during pre-harvest and post-harvest is urgently necessary it causes mass losses of grains. In several countries, about 15% of grains are lost harvesting or post-harvesting stages. The Food and Agricultural Organization (FAO) has estimated this loss up to 40% in India. Among the culprits of these losses, coleopteran insect species play major roles. Among coleopterans, red flour beetle, Tribolium castaneum causes loss of grains and food products to larger extent in post-harvest stage. T. castaneum is a secondary pest with a wide host range infesting almong, barley, beans, ground nuts, lentils, maize, oat, peas, rice, rye, sorghum, wheat and other processed grain products. Adults and larvae attack grains already damaged by primary pest and feed mainly on the germ. For the management of T. castaneum population, several approaches including synthetic insecticides have been applied with lots of success but leaving several environmental and human health issues too. To minimize these adverse effects, plant derived volatile chemicals i.e. essential oils and its constituents alone or in combination have been used and got promising results. Since these are volatile, non-persistent and biodegradable, essential oil based formulations can be used for the management of T. castaneum at large as green eco-friendly insecticide

Chemical Composition of Essential Oils from the Leaves of Schinus molle and Cupressus sempervirens and their Insecticidal Activity against Oryzaephilus surinamensis (Coleoptera: Silvanidae)

Essential Oils (EOs) from aromatic plants were reported to have an insecticidal activity against several insects and could be an alternative to synthetic insecticides. The aim of this study is to determine the chemical composition of two plants (Schinus molle and Cupressus sempervirens) grown in Algeria and to investigate their insecticidal activity against the sawtoothed grain beetle Oryzaephilus surinamensis, a secondary pest that may alter seriously the proprieties of some food products. EOs were extracted by hydrodistillation using Clevenger apparatus and analyzed by Gas Chromatography/Mass Spectrometry (GC/MS). The analysis determined that the major components of S. molle EO are β-Eudesmol (15.19 %), Elemol (13.97 %), D-Limonene (9.89 %), Spathulenol (9.33 %) and β-Phellandrene (7.72 %) while those of C. sempervirens EO are Cedrol (44.81 %), α-Pinene (15.71 %) and neoiso-Dihydrocarveol acetate (9.7 %). The biological activity of EOs was evaluated by fumigation and repellency at different concentrations and exposure times. Fumigation toxicity bioassays showed maximum efficacy was reached at a concentration of 100 μL/L of air for the two kinds of EOs (90-100 %). Repellency tests revealed that S. molle EO was moderately repellent (55.62 %), while C. sempervirens EO was highly repellent (66.25 %). In fact, the EO of the experimental plants can be incorporated into insecticidal formulations and might be efficient as alternative to synthetic insecticides for O.surinamensis control. However, other tests need to be performed on other life stages of the insect.

Coccoidea infesting goldenberry, Physalis peruviana L. with ecological and control studies of the cotton mealybug, Phenacoccus solenopsis tinsley (Hemiptera, Coccomorpha, Pseudocccidae) from Egypt

The promising untraditional crop, Goldenberry, Physalis peruviana L. rapidly cultivated in many countries as a demand of fruit as in fresh markets; medicinal purposes; developing processing industry and rapid growing of exportation. Unfortunately, the plant recognized highly infesting by many Coccoidea species in Qalyubiya Governorate, Egypt thus experiments conducted to survey, population fluctuations and control of the most found prominent species. During the survey study period a total of four Coccoidea species following four genera belonging to two families of Supper family Coccoidea were recorded three of them were recorded for the first time infesting Physalis peruviana L as well as a total of six predators and two parasitoids recorded associated with the collected species. Data obtained indicated that, the most dominant Coccoidea species was the cotton mealybug, Phenacoccus solenopsis causing a severe infestation reducing the quantity and quality of the goldenberry crop therefore the study on this pest covers a population fluctuations and number of generations as well as its associated natural enemies during two successive growing seasons of 2019-2020 and 2020-2021. The results obtained clarified that P. solenopsis Tinsley have three peaks of abundance in both seasons in the selected goldenberry orchards with a very low effective of the recorded parasitoid, Dicrodiplosis manihoti Harris. The correlation of the selective abiotic factors (maximum & minimum temperature and relative humidity) and biotic factors (natural enemies) with the population fluctuation of the cotton mealybug were studied. A control study conducted to evaluate the highest and safest alternative pesticide to reduce the pest especially with lake of sufficient parasitoid found during the period of study. This study could be a great help to understand the endemicity of the species and the best way to control without several problems such as, pesticide residual, pest resistance, secondary pest outbreaks.

The Hazel Stem Borer, Agrilus pseudocoryli (Coleoptera: Buprestidae), as a Pest of Hybrid Hazelnuts.

Nuts from hybrid hazels (Corylus americana Walter × Corylus avellana L.) are a burgeoning, novel industry for the Great Lakes region of the United States. As such, scant information exists about the pest complex, although stem-boring beetles in the genus Agrilus Curtis (Coleoptera: Buprestidae) have been noted by growers as potential pests. Here, we report results of a comprehensive survey of 186 plants in a hybrid hazel planting consisting of nine cultivars in southeastern Minnesota affected by stem borers. Sixteen percent of the hybrid hazel plants exhibited between 25 and 100% buprestid associated dieback. Morphological and molecular identification of the adult and larval buprestids colonizing hybrid hazel plants revealed that the hazel stem borer, Agrilus pseudocoryli Fisher, was the only species present. Adult A. pseudocoryli were observed on plants between 8 June and 13 July 2021. Plants with higher damage ratings from the hazel stem borer were more likely to exhibit signs of eastern filbert blight (Anisogramma anomala Peck), a fungal pathogen virulent to C. avellana. Some hazel cultivars were more susceptible to damage from stem borers than others. Taken together, our findings suggest that the hazel stem borer has the potential to impact hybrid hazelnut yield. We speculate that a regional drought may have promoted increased populations of the hazel stem borer, as native Agrilus species are often secondary pests that become problematic when environmental stresses decrease host resistance. More research is needed to elucidate interactions between hazels, buprestid pests, and environmental conditions to predict impacts on crop yields.

Effect of UV-C followed by storage on the fungal growth and aflatoxins content and storability characteristics of sesame (Sesamum indicum) seeds

BackgroundUV-C has been suggested as an alternative technology in controlling food spoilage by primary and secondary pests. Its effects on the storability characteristics of sesame seeds during storage were evaluated. MethodsThe UV-C (0, 2.5, 5.0 and 10 kJ m−2) was applied to explore its Effect on the fungal growth, aflatoxin content, water activity (aw), colour and free fatty acid content (FFA) of sesame seeds. ResultsApplying the UV-C caused a significant reduction in the fungal growth, aw, and the lightness (L* value) of sesame seeds in fresh and stored samples. However, significant increases (p < 0.05) in a* and b* values and the FFA of the sesame seeds were observed. Interestingly, the aflatoxins were not detected in the UVC-treated seeds even after storage for 12 months. The Partial Least Squares regression (PLS) analysis indicated that the application of 5.0 kJ m−2 followed by six months of storage reveals the greatest valid dose for UV-C treatments of sesame seeds. ConclusionUV-C treatment potentially shows effective quarantine security as an alternative method to chemical disinfection procedures to prolong the shelf life and improve the storability characteristics of sesame seeds.

Calculation of ecological and economic damage in forest management from insect pests

The work is devoted to the development of the methodology for assessing ecological and economic damage from insect pests in dark coniferous forests of Siberia. On the basis of field data and generalised methodology, the results of calculation of income losses from direct and indirect damage caused by the impact of Ussuri Polygraphus on the fir forests of Krasnoyarsk Krai are presented. The complex monetary assessment is made on the basis of losses of marketable qualities of wood, oleoresin, fir boughs and loss of ecological functions - carbon-depositing, oxygen-producing and water-protecting. The proposed variant of calculation is possible to adapt the assessment of damage caused by various secondary pests and as a result of mass impact of the Siberian silkworm.

Behavioral interactions of bed bugs with long-lasting pyrethroid-treated bed nets: challenges for vector control

BackgroundWidespread vector control has been essential in reducing the global incidence and prevalence of malaria, despite now stalled progress. Long-lasting insecticide-treated nets (LLINs) have historically been, and remain, one of the most commonly used vector control tools in the campaign against malaria. LLINs are effective only with proper use, adherence, retention and community adoption, which historically have relied on the successful control of secondary pests, including bed bugs. The emergence of pyrethroid-resistant bed bugs in malaria-endemic communities and failure to control infestations have been suggested to interfere with the effective use of LLINs. Therefore, the behavioral interactions of bed bugs with commonly used bed nets should be better understood.MethodsTo investigate the interactions between bed bugs (Cimex lectularius L.) and LLINs, insecticide-susceptible and pyrethroid-resistant bed bugs were challenged to pass through two commonly used LLINs in two behavioral assays, namely host (blood meal)-seeking and aggregation-seeking assays. The proportions blood-fed and aggregated bed bugs, aggregation time and mortality were quantified and analyzed in different bed bug life stages.ResultsOverall, both the insecticide-susceptible bed bugs and highly resistant bed bugs showed a varying ability to pass through LLINs based on treatment status and net design. Deltamethrin-treated nets significantly impeded both feeding and aggregation by the susceptible bed bugs. While none of the tested LLINs significantly impeded feeding (passage of unfed bed bugs through the nets) of the pyrethroid-resistant bed bugs, the untreated bed net, which has small mesh holes, impeded passage of fed bed bugs. Mortality was only seen in the susceptible bed bugs, with significantly higher mortality on deltamethrin-treated nets (63.5 ± 10.7%) than on permethrin-treated nets (2.0 ± 0.9%).ConclusionsCommonly used new LLINs failed to prevent the passage of susceptible and pyrethroid-resistant bed bugs in host- and aggregation-seeking bioassays. The overall low and variable mortality observed in susceptible bed bugs during both assays highlighted the potential of LLINs to impose strong selection pressure for the evolution of pyrethroid resistance. Already, the failure to control bed bug infestations has been implicated as a contributing factor to the abandonment or misuse of LLINs. For the first time to our knowledge, we have shown the potential of LLINs in selecting for resistant secondary pest populations and so their potential role in stalling malaria control programs should be further investigated.Graphical The emergence of pyrethroid-resistant bed bugs in malaria-endemic communities may interfere with the effective use of pyrethroid-impregnated bed nets. We assessed the interactions of two bed bug strains with commonly used bed nets using two behavioral assays, namely host (blood meal)-seeking by unfed bed bugs and aggregation-seeking by freshly fed bed bugs. These assays assessed the passage of bed bugs through various bed nets in response to host cues and aggregation stimuli, respectively. Conditioned paper is a section of file folder paper that has been exposed to bed bugs and has been impregnated with feces and aggregation pheromone; it is attractive to aggregation-seeking fed bed bugs. An unconditioned ramp is a similar section of file folder paper that allows bed bugs to traverse the bed net and gain access to a blood-meal source.

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.

Foliar Residual Toxicity of Insecticides to Brassica Pests and Their Natural Enemies.

Overuse of pesticides can result in the development of resistance, secondary pest outbreaks, and pest resurgence due to a reduction in natural enemies. The present study compares the residual toxicity of lambda-cyhalothrin, a relatively nonselective insecticide, with abamectin, indoxacarb, and spinosad, compounds which have been reported to be less harmful to arthropod natural enemies. Two key cosmopolitan pests of crucifer crops, (Plutella xylostella) and (Myzus persicae), and two of their respective hymenopteran parasitoids, (Cotesia vestalis) and (Aphidius colemani) were used as representative pests and natural enemies. The pyrethroid lambda-cyhalothrin was found to be the most persistent toxicant against both pest and both parasitoid species tested, while the lactones abamectin and spinosad were the least persistent toxicants. A leaf wax stripping technique was used to compare the contact toxicity of insecticide residues against adult C. vestalis and A. colemani in the epicuticular wax layer. For each compound, removal of epicuticular wax reduced the 24 h residual toxicity (LC50) of fresh deposits (day 0) by about an order of magnitude against C. vestalis. A second residual toxicity experiment showed that removal of epicuticular wax significantly reduced the residual toxicity of each compound against A. colemani at 0, 7, and 14 d after application, with little or no detectable residual activity for the oxadiazine indoxacarb or abamectin/spinosad respectively after 14 d. The present data supports the view that in addition to the intrinsic toxicity of insecticides to natural enemies, differences in their persistence as foliar residues should also be considered in IPM systems.

Dangerous liaisons of three key secondary stored-product pests in cracked maize

The current study examines the relationships of Oryzaephilus surinamensis (L.) (Coleoptera: Silvanidae) with Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) and Tenebrio molitor L. (Coleoptera: Tenebrionidae) through Gaussian and Poisson regression models on cracked maize. For this purpose, variable temperatures (25 °C, 30 °C, and 35 °C), relative humidities (RH) (55% and 75%), exposure intervals (65 days, 130 days, and 195 days), and insect combinations (the insect species alone and the combinations per 2 or 3 species that included O. surinamensis) were utilized. Poisson model was the most suitable for the response insects alive while Gaussian model for the weight loss. The increase of temperature from 25 °C to 30 °C and from 30 °C to 35 °C led to a gradual decrease of insects alive and a gradual increase of weight loss, while the enhancement of RH caused increase of both responses. At the 195 days of storage period, insects alive reduced whereas weight loss amplified. The combinations of insects that led to the highest and the lowest numbers of insects alive were O. surinamensis alone and T. molitor alone respectively. The most damaging combination was O. surinamensis-T. molitor while the least damaging was T. molitor alone. Findings of the current study enrich the existing knowledge of the relationships of three secondary stored-product insects in processed maize. The complexity of their coexistence is linked with the forecast of the contingent damage of the insect activity during the storage period.