Nezara Viridula Research Articles

Selective responses of Trissolcus basalis and Telenomus podisi to chemical footprints of preferred hosts

AbstractChemical trails of the hosts (footprints) are important cues for the host searching behaviour of egg parasitoids of the family Scelionidae. The present study aims to determine the influence of the footprints of three neotropical stink bugs (Euchistus heros, Dichelops melacanthus and Nezara viridula) on the foraging behaviour of two parasitoids, Trissolcus basalis and Telenomus podisi, as well as a possible selective response to fooprints of their preferred hosts. Accordingly, Tr. basalis and Te. podisi females are allowed to forage on open arenas where E. heros, D. melacanthus or N. viridula had walked or on open arenas that had been treated with samples of an extract from each stink bug's footprints. Hexane extracts of stink bug footprints are obtained from solvent‐washed Petri dishes where insects were allowed to walk for 24 h, and these extracts were analyzed by gas chromatography‐flame ionization detection and gas chromatography‐mass spectrometry. Each parasitoid responds selectively to the footprints of their preferred host (Tr. basalis to footprints of N. viridula and Te. podisi to footprints of E. heros). Twenty‐six compounds comprising of C18 to C35 (saturated and unsaturated) and methyl branched hydrocarbons were identified in extracts of E. heros, D. melacanthus and N. viridula, respectively. There are significant differences in the total amount of the compounds identified in the footprint stink bug's extracts and also a difference in the amounts of individual compounds. In addition, the behavioural assays showed that footprints of stink bugs are stimuli that are used by egg parasitoids to search, discriminate and selectively locate their preferred host.

STINK BUG POPULATION FLUCTUATION AND CONTROL IN SOUR PASSION FRUIT ORCHARDS IN SOUTHERN BRAZIL

ABSTRACT Sour passion fruit (Passiflora edulis Sims, 1818) crops in Brazil are drawing attention due to the national production, and the increasing consumption of this fruit as fresh and processed products. However, fruit losses due to damages caused by stink bugs (Hemiptera: Coreidae) are concerning to fruit growers in southern Brazil. The objective of this study was to evaluate the population fluctuation and control of stink bugs in P. edulis crops grown in the 2013-2014 and 2014-2015 crop seasons in Araquari, SC, Brazil, using natural and synthetic insecticides. The stink bug population was evaluated using the 0.25 m2 frame technique. The evaluations were carried out weekly during the two crop seasons. The species and distribution of stink bugs in the different parts of the plant were evaluated. The insecticides and rates used were: Neenmax (azadirachtin 1.0%) at 10 mL L-1; Orobor N1 (N-citric acid 1.0% + 0.20% B) at 2 mL L-1; and Decis 25 EC (deltamethrin 2.5%) at 1 mL L-1, diluted in aqueous solution. Specimens of three stink bug species where found: 86% Diactor bilineatus (Hemiptera: Coreidae); 13.5% Holhymenia histrio (Hemiptera: Coreidae), and 0.5% Nezara viridula (Hemiptera: Pentatomidae). The D. bilineatus species presented higher frequency, constancy, and dominance during the evaluated crop seasons; 64% of the stink bugs were found on fruits, 18.5% on leaves, 7.3% on floral buds, 5.8% on flowers, and 4.4% on branches. The use of azadirachtin or deltamethrin was efficient to reduce the stink bug infestation and the number of P. edulis withered fruits.

Stink Bugs Nymph and Adult Biology and Adult Preference on Cultivated Crop Plants in the Southern Brazilian Neotropics.

Laboratory studies were conducted with Dichelops furcatus (F.), Euschistus heros (F.), and Nezara viridula (L.) (Heteroptera: Pentatomidae) aiming to evaluate nymph and adult biology and adult preference for immature reproductive structures of the cultivated plants, soybean, Glycine max (L.) Merrill (Fabaceae), wheat, Triticum aestivum L. (Poaceae), and canola, Brassica napus L. var. oleifera (Brassicaceae). Considering the survivorship for D. furcatus nymphs, it was greater on soybean and wheat, for E. heros nymphs it was greater on soybean compared to canola and wheat, and for N. viridula nymphs the survivorship was greater on soybean and canola. Dichelops furcatus nymphs developed faster on soybean and wheat, and E. heros and N. viridula nymphs developed faster on soybean and canola. Body weight at adult emergency for D. furcatus was greater on soybean and wheat, and for E. heros and N. viridula, it was greater on soybean. Adult survivorship and longevity were similar on soybean/wheat/canola for D. furcatus and N. viridula, and greater on soybean for E. heros. Reproduction and weight gain of adults were greater on soybean and wheat for D. furcatus, and on soybean for E. heros; N. viridula reproduced only on soybean and tended to gain greater body weight in this food source. As expected, soybean considering its superior nutritional quality was, in general, the best food. These laboratory studies coupled with field observations allow to conclude that the sequence of soybean/wheat/canola crops in the area studied forms a 'green bridge' that favor stink bug populations abundance in southern Brazilian neotropics.

An Established Population of the Southern Green Stink Bug, Nezara Viridula (Linnaeus), in Washington State

An Established Population of the Southern Green Stink Bug, Nezara Viridula (Linnaeus), in Washington State

Electrophysiological Responses of Eighteen Species of Insects to Fire Ant Alarm Pheromone.

Olfaction plays a dominant role in insect communication. Alarm pheromones, which alert other insects of the same species of impending danger, are a major class of releaser pheromones. The major components of alarm pheromones in red imported fire ants, honeybees and aphids have been identified as 2-ethyl-3,6-dimethylpyrazine (2E-3,6-DP), isopentyl acetate (IPA), and E-β-farnesene (EβF), respectively. In this study, electroantennography (EAG) responses to EDP (a mixture of 2-ethyl-3,6-dimethylpyrazine and 2-ethyl-3,5-dimethylpyrazine), IPA and EβF were investigated in a wide range of insect species. Beside imported fire ants, the EDP (2-ethyl-3,6(5)-dimethylpyrazine) elicited significant EAG response from all other tested insects, including six ant species and one hybrid ant, honeybee, bagrada bug, lady beetle, housefly, small hive beetle, yellow fever mosquito, termite, bedbug, water hyacinth weevil, southern green stink bug and two aphid species. In contrast, IPA elicited significant EAG response only in the honeybee, red imported fire ant, an Aphaenogaster ant, and the water hyacinth weevil. The EβF only elicited EAG responses in two aphids, small hive beetle and housefly. The results clearly indicate that EDP can be detected by widespread insect species that did not coevolve with S. invicta and further suggested alkylpyrazine may activate multiple generally tuned olfactory receptors (ORs) across a wide number of insect species.

Proteases and nucleases across midgut tissues of Nezara viridula (Hemiptera:Pentatomidae) display distinct activity profiles that are conserved through life stages

The southern green stink bug, Nezara viridula is a polyphagous pest of commercially important crops during both nymph and adult stages. This insect has recently transitioned from a secondary agricultural pest to one of primary concern. Novel management solutions are needed due to the limited effectiveness of current control strategies. We performed biochemical and transcriptomic analyses to characterize digestive enzymes in the salivary glands and along midgut tissues of N. viridula nymphs and adults fed on sweet corn. The digestive profiles were more distinct between midgut regions (M1 to M3) than between life stages. Aminopeptidase and chymotrypsin activities declined from the M1 (anterior) toward the M3 midgut region. Cysteine protease activity was higher in the M2 and M3 regions than in M1. Differences in sensitivity to chymotrypsin inhibitors between midgut regions suggest that distinct genes or isoforms are expressed in different regions of the gut. In nymphs, DNA and RNA degradation was higher in M1 than in M3. Adult nuclease activity was low across all midgut regions, but high in salivary glands. The differences in protease activities are reflected by transcriptomic data and functional enrichment of GO terms. Together, our results show that different regions of the digestive tract of N. viridula have specific and distinct digestive properties, and increase our understanding of the physiology of this organism.

The Principal Salivary Gland Is the Primary Source of Digestive Enzymes in the Saliva of the Brown Marmorated Stink Bug, Halyomorpha halys.

The brown marmorated stink bug, Halyomorpha halys, is an invasive, phytophagous stink bug of global importance for agriculture. Tissue-specific transcriptomic analysis of the accessory salivary gland, principal salivary gland (PSG) and gut resulted in identification of 234 putative protease and 166 putative nuclease sequences. By mapping the previously reported proteomes of H. halys watery saliva (WS) and sheath saliva to protein sequences translated from the assembled transcripts, 22 proteases and two nucleases in the saliva were identified. Of these, 19 proteases and both nucleases were present in the WS. The majority of proteases and nucleases found in WS were derived from the PSG, in line with ultrastructural observations, which suggest active protein synthesis and secretion by this tissue. The highly transcribed digestive proteases and nucleases of H. halys were similar to those of the southern green stink bug, Nezara viridula, indicating that these pentatomid stink bugs utilize a similar suite of proteases and nucleases for digestion of plant material. The comprehensive data set for the H. halys salivary glands and gut generated by this study provides an additional resource for further understanding of the biology of this pestiferous species.

Comparative Efficacy of Imidacloprid as Seed Treatment Insecticide against Sucking Insects and their Predators in the Wheat Crop

Sucking insects are the most serious insect pests in wheat crops; the harmful effect of aphid in wheat plants is due to sucking of plant sap, honeydew excretion and causing many diseases by transport of plant viruses. The experiment was carried out at Sakha Agric. Res. Station farm during 2017-2018 on wheat Giza 171 growing season. The insecticide used is Imidacloprid (Nofedor 600 FS.) The present study was designed to evaluate comparative efficacy of imidacloprid as seed dressing formulation against sucking insects (Schizaphis graminum, Nezara viridula, Empoasca spp.) as well as their predators; Chrysoperla carena, Labidura riparia, Scymunus spp. and true spiders in two types of wheat sowing (Drill and Broadcast) in the wheat crop field. The results according to analysis of variance showed that there was a significant variation among the insect’s reduction in all-season periods as a result of treatment of the wheat seeds before sowing with imidacloprid in the Broadcast and drill sowing. Whereas there is no significant effect of the treatment when comparing S. graminum in different sowing methods, also there was a non-significant effect of the treatment on S. graminum in broadcast method versus N. viridula, Empoasca spp. and predators. While, the number of seeds/spikes, Weight of 100 seeds (gm) and the Germination increasing % in Broadcast sowing were more than that in Drill sowing by 1.31,1.11 and 1.11 respectively. Thus, it could be concluded that the broadcast sowing is suitable economically for farmers than drill sowing methods when using imidacloprid as seed dressing before cultivation for sucking insect control as well as its predators.

Biomechanics of fore wing to hind wing coupling in the southern green stink bug Nezara viridula (Pentatomidae)

Stink bugs have wing coupling mechanisms to synchronize flapping of their wings. The wing coupling is performed through a clamp-like structure on the fore wing (i.e. hemelytron) and a rolled margin on the hind wing. Here we used modern imaging techniques to investigate structural characteristics and material composition of the wing coupling of the stink bug Nezara viridula. We found that the surfaces of the clamp-like structure and the rolled margin are covered by highly-sclerotized microtrichia, which are expected to reduce friction between the wings during flapping flight. Micro-force measurements showed that fore and hind wings can be coupled only in certain angles ranging from 40.6° to 267.7° The results further showed that the force required to uncouple fore and hind wings is maximal for a range of angles which they make with each other during flight (127.1°–238.9°). In contrast to previous observations on some other insect species, the removal of the wing coupling in stink bugs led to complete loss of flight ability. In summary, we concluded that the shape, material composition and orientation of the coupling structure guarantee a robust fore wing to hind wing coupling during flight and a fast, easy uncoupling at rest. Statement of significanceAlthough the coupling mechanism of insect fore wing and hind wing has long been described, the functionality of this mechanism still remains largely unknown. In the present work, using a combination of modern imaging techniques and mechanical testing, we studied the functional morphology of the fore wing-hind wing coupling mechanism of the stink bug Nezara viridula. Our study reveals the crucial role of the mechanism in the flight ability of the stink bug and sheds light on the structure-property-function relationships of the functional diptery in insects.

LABORATORY EVALUATION OF BENGKULU ISOLATES OF Beauveria bassiana AND Metarhizium anisopliae AGAINST COFFEE BERRY BORER, Hyphotenemus hampei, USING SPRAYING METHOD

Laboratory Evaluation of Local Isolates of Beauveria bassiana and Metarhizium anisopliae against Coffee Berry Borer, Hyphotenemus hampei, using spryaing method. Beauveria bassiana Bals (Vuillemin) and Metarhizium anisopliae (Metschnikoff) Sorokin are two species of fungi that have been studied widely and used as biological control of various insect pests, including coffee berry borer (CBB), Hyphotenemus hampei Ferrari. Laboratory studies were done in June – July 2017, to evaluate local isolates of both fungi species against CBB, the most destructive insect pest of coffee worldwide, including in Indonesia. B. bassiana was isolated from dead sweet potato weevil (Cylas formicarius) and green stink bug (Nezara viridula), and from soil. M. anisopliae was isolated from soil. The pure cultures of the fungi were mass-cultured on corn based media. The conidia harvested from 4 week colonies was hand sprayed directly upon CBB adults (females) and damaged coffee berry at the concentration of 109 ml-1. In additions, the conidia of B. bassiana isolated from C. formicarius alone was diluted to 106- 109 ml-1 and applied to damaged coffee berry. The results showed that when the conidia were applied directly upon the insects, the mortality of beetle were higher in B. bassiana than in M. anisopliae treatments. Pooled data indicated that B. bassiana isolated from death insects significantly caused higher mortality than did M. anisopliae isolated from soil. Beetle mortality was 76.7 and 80.0% for B. basiana, and 60.3 and 60% for M. anysopliae treatments. Application upon damage coffee berry indicated much lower mortality. Application of higher concentration upon damaged coffee berry resulted higher mortality, but data are not consistent. The mortality of CBB larvae was much less and negligible even at the highest conidia concentration.

Comparison of Two Insect-Collecting Devices for Trapping Stink Bugs (Hemiptera: Pentatomidae)

Abstract Stink bugs (Hemiptera: Pentatomidae), including Euschistus spp., Chinavia hilaris (Say), and Nezara viridula (L.), are economic pests in most fruit, grain, vegetable, and row crops in the ...

Kaolin nano-powder effect on insect attachment ability

The present study investigates under controlled conditions the effect of kaolin particle film on reduction of insect attachment ability. Two economically important polyphagous insect pests characterized by different attachment devices were tested, the Southern green stink bug Nezara viridula (Heteroptera: Pentatomidae) and the Mediterranean fruit fly Ceratitis capitata (Diptera: Tephritidae). We performed traction force experiments with females pulling on treated (covered with kaolin particle film) and untreated (control) natural (leaf surfaces with different morphological traits) and artificial (hydrophilic and hydrophobic glass) surfaces. The data demonstrated that insect adhesion is heavily affected by kaolin particle film in both tested species. The degree of reduction of insect adhesion to the treated substrates compared with the untreated ones differed according to the kind of treated substrate owing to its initial wettability and morphology (presence of trichomes). To unravel the insect adhesion reduction mechanism of kaolin particle film, we evaluated the safety factor for females before and after walking on treated surfaces and analyzed under cryo-SEM the tarsal attachment devices of N. viridula and C. capitata after walking on treated surfaces. We observed contamination by the kaolin nanoflakes in both the smooth pads of the bug and the hairy pads of the fly. The present study can help to better understand the mechanism of action of kaolin particle film and can contribute to develop future physical control barriers against pest insects, particularly relevant owing to the need to reduce the negative impacts of pesticides on environment and human health.

Effectiveness Test of Tagetes erecta L Powder and Cattle Urine Waste that Potentially Repelent ont Boring Pests of Nezara viridula Pods in Soybean (Glycine max L) in Patumbak Subdistrict, Deli Serdang, North Sumatra

Soybean plants (Glycine max) are the third most important food commodity crop after rice and corn. Soybean production continues to be improved in meeting community needs, but efforts to increase soybean production still face problems, namely green ladybird pest (N. viridula L.). One alternative to control soybean pod sucking insects that are relatively safe, inexpensive, and easily obtained is the use of vegetable insecticides. Vegetable insecticides do not quickly cause pest resistance, are synergistic, and their use can be combined with other pest control techniques. One of them is by using Tagetes erecta plants combined with cow urine as a vegetable insecticide. The use of repellents generally does not directly kill insects, but rather serves to reject the presence of insects, mainly due to the pungent smell. The use of cow urine as a mixture of biopesticides contains growth stimulants and contains repellents for several types of insect pests. This study aims to determine the effectiveness of Tagetes erecta in reducing the population of N.viridula pests in soybean plants (Glycine max L.Merr). Non Factorial RAK with 5 levels of treatment and 5 replications. Hopefully with this study farmers can take advantage of tagetes erecta and cow urine waste that can be used as natural pesticides and can be used as a control for Hama Nezara viridula which is environmentally friendly and economic.

Experimental assessment of the biosafety of Trissolcus japonicus in New Zealand, prior to the anticipated arrival of the invasive pest Halyomorpha halys

Despite numerous interceptions at the border, the brown marmorated stink bug (BMSB), Halyomorpha halys Stal (Hemiptera: Pentatomidae), is not yet established in New Zealand. Nevertheless, a classical biocontrol programme using the egg parasitoid Trissolcus japonicus Ashmead (Hymenoptera: Scelionidae) has been initiated in anticipation of its likely arrival. The potential host range of the parasitoid in New Zealand was investigated by importing parasitised BMSB eggs into quarantine from Newark, DE, USA. Egg masses of seven species of Pentatomidae, including one sub-species, were individually exposed to naive mated female T. japonicus in no-choice laboratory experiments. The results showed that predatory Cermatulus nasalis nasalis, C. nasalis hudsoni and Oechalia schellenbergii, and the phytophagous Monteithiella humeralis, Dictyotus caenosus, Glaucias amyoti, and Cuspicona simplex are all within the physiological host range of T. japonicus, although not all appeared to be equally susceptible to parasitism. No development or emergence of T. japonicus from eggs of the cosmopolitan pentatomid plant pest Nezara viridula were observed. The likely ecological consequences of releasing T. japonicus in New Zealand are discussed, as is the subsequent decision of New Zealand’s Environmental Protection Authority to approve release of the parasitoid once BMSB arrives in New Zealand.

The complete mitochondrial genome of Plautia crossota (Hemiptera: Pentatomidae)

In this study, we elucidated the complete mitochondrial genome (mitogenome) of Plautia crossota. The circular mitogenome is 16,809 bp long, including 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes, and a non-coding control region. The overall base composition is as follows: A, 41.6%; T, 32.75%; C, 14.84%; G, 10.81%; a slight A + T bias of 74.35%. Phylogenetic analysis of 20 species of Pentatomoidea revealed that Plautia crossota was closer to Nezara viridula.

The underestimated role of pest pentatomid parasitoids in Southern South America

Stink bugs are pests of economic importance of extensive crops (commodities) in the Neotropics, particularly in Southern South America. They are abundant, have a broad geographical distribution, and cause severe damage. Main species include the Neotropical brown-stink bug, Euschistus heros (F.), the red-banded stink bug, Piezodorus guildinii (Westwood), the Southern green stink bug, Nezara viridula (L.), the green-belly stink bugs, Dichelops furcatus (F.), and D. melacanthus (Dallas), and the brown-winged stink bug, Edessa meditabunda (F.). The management of these pest species on crops is complex because they can cause economic damage in low numbers, and it is difficult to control by the commonly used insecticides. Therefore, biological control appears as the most important tactic to be implemented in stink bug management programs. Among the many natural enemies present on the various agroecosystems, egg parasitoids (Hymenoptera) and parasitoids of adult stink bugs (Diptera and Hymenoptera) are the most promising groups to be exploited as biological control agents of pest species. Despite attempts in the past, implementation of biological control of stink bugs on major commodities in Southern South America still remains at a low level of adoption, and its high potential is, generally, underestimated. In this review article, we present extensive data from the literature on the two main groups of biological control agents referred above. Moreover, we discuss ways to promote biological control as the most important tactic to manage stink bugs in Southern South America.

Female competition for availability of males in insects: the Nezara viridula (Linnaeus, 1758) model.

Multimodal communication in solitary stinkbugs enables them to meet, mate and copulate. Many plant-dwelling species exchange information during the calling phase of mating behavior using substrate-borne vibratory signals. A female-biased gender ratio induces rivalry and competition for a sexual partner. Female competition for males, first described among Heteroptera in three stinkbug species, revealed species specific differences and opened the question of plasticity in individually emitted temporal and frequency signal characteristics during calling and rival alternation. To address this question and gain an insight into the mechanisms underlying stinkbug female rivalry, we compared the characteristics of alternated signals in the southern green stinkbug Nezara viridula (Linnaeus, 1758) (Hemiptera: Pentatomidae). Compared to male rivalry, female rivalry is more complex, lasts longer and runs through successive phases by a combination of different song types. The male pheromone triggers alternation between females, producing song pulses that occasionally overlap each other. One female initiates the rivalry by changing individual pulses into pulse trains of three different types. The competing female alternates with pulses of changed temporal characteristics at lower levels of rivalry and by varying the frequency characteristics of pulse trains at higher levels. During female rivalry, the male either stops responding or occasionally emits calling and courtship signals in response to the female that has produced signals of steady temporal characteristics. Female rivalry shows complex and species specific patterns of information exchange at different levels with a broad-range variation of temporal and frequency characteristics of, until now, unidentified vibratory emissions.

Ecosystem services and disservices by birds, bats and monkeys change with macadamia landscape heterogeneity

AbstractThe relative importance of ecosystem services and disservices can change with landscape structure in a poorly understood way.We compare the impact of biocontrol, provided by bats and birds, with that of crop raiding by vervet monkeys on yield in South African macadamia orchards. Insectivorous bats and birds are known to feed on macadamia pest insect species, like the macadamia nut borer or the green vegetable bug. Vervet monkeys move into the orchards during the day to feed on premature macadamia nuts. Bats, birds and monkeys benefit from patches of natural vegetation adjacent to orchards.With exclusion experiments (four treatments: day, night, day and night, control) we quantified the relative importance of biocontrol and crop raiding on yield, comparing two different landscape settings of the orchards, a natural and a human‐modified.Crop raiding occurred only close to natural vegetation and caused yield losses of about 26%. Biocontrol by bats and birds was higher near natural vegetation, but still significant in human‐modified landscapes, at up to 530 m distance to forest patches. Prevented biocontrol through the exclusion of bats and birds resulted in yield losses of up to 60%.Effects of biocontrol by bats and birds (USD ~5,000 ha/year) were economically more important than the losses of crop raiding (USD ~1,600 ha/year). As both are linked to the vicinity of forest patches, the removal of natural vegetation to limit monkey abundances would also limit biocontrol service provision.Synthesis and applications. This study highlights the high economic benefits of biocontrol by bats and birds, which outweighed negative impacts through yield losses caused by crop raiding monkeys. Management practices to prevent crop damage, such as guarding, excluding vertebrates or removal of adjacent natural vegetation, would also limit access for bats and birds and the great economic benefits provided by their biocontrol. Ecosystem services by bats and birds can be promoted by the exposure of artificial roost and nest sites, but research into species‐specific preferences is needed. The education of farmers is crucial, as many are unaware of the benefits from birds and bats and the fact that these benefits can outweigh the disadvantages of the monkeys’ crop raiding.

Candidate genes coding for odorant binding proteins and chemosensory proteins identified from dissected antennae and mouthparts of the southern green stink bug Nezara viridula

The southern green stink bug Nezara viridula (Hemiptera: Pentatomidae) is a highly polyphagous pest that can significantly impact many major crops worldwide. Insect odorant binding proteins (OBPs) and chemosensory proteins (CSPs) transport chemicals and play critical roles in chemoreception. Studies on N. viridula OBPs and CSPs should increase our overall understandings on chemosensory systems and chemical ecology of stink bugs, which may lead to improved pest control. In this study, we identified candidate genes encoding putative OBPs and CSPs in N. viridula by generating transcriptomes from dissected antennae and mouthparts. In total, the 42 unigenes were identified coding for OBPs (34 Classic OBPs and eight Plus-C OBPs) and 13 unigenes coding for CSPs. Expression profiles of OBP- and CSP -encoding genes were compared between antennae and mouthparts based on FKPM values. Candidates for antenna-predominant OBPs and CSPs were selected for real-time quantitative PCR analyses. Analyses of tissue expression profiles revealed that 17 OBP-encoding genes, and four CSP genes were primarily expressed in antennae, suggesting their putative roles in perception of volatiles. The sex-biased expression patterns of these antenna-predominant genes suggested that they may have important functions in reproduction of the insect. This is a systematic analysis on OBPs and CSPs in a stink bug, providing a comprehensive resource for future functional studies not only for N. viridula, but also for other stink bugs as well.

The Cotton Boll: Temporal Susceptibility of the Boll Wall to Stylet Penetration by Hemipteran Pests

Cotton (Gossypium hirsutum L.) is a high‐value cash crop that is injured by various hemipteran insects, including lygus bugs (mirids) and stink bugs (pentatomids). Stink bugs can transmit pathogens that cause seed and boll rot of cotton, and lygus bugs can also transmit pathogens. However, the temporal susceptibility to breaching of the boll wall by stink bugs and related species was unknown. Our objective was to compare known estimates of stylet penetration for mirids (Lygus lineolaris Palisot de Beauvois and Pseudatomoscelis seriatus Reuter) and pentatomids [Chinavia hilaris Say, Euschistus obscurus (Palisot), Euschistus servus (Say), Euschistus tristigmus (Say), Nezara viridula (L.), Oebalus pugnax (F.), Piezodorus guildinii Westwood, and Thyanta custator accerra McAtee] against observed minimum boll wall thickness in multiple entries from four Gossypium species to determine the time at which bolls initially become susceptible to stylet penetration. Results show that P. seriatus could not breach the boll wall. Lygus lineolaris could breach the wall at ≤7 d after flowering in G. herbaceum L. and in select entries of G. hirsutum. All the pentatomids could breach the boll wall at 1 d after flowering, and virtually all could continue to breach the wall throughout the entire production season. Monitoring efforts for stink bugs may need to be implemented at boll set to mitigate introduction of pathogens and yield losses given the season‐long susceptibility to stink bugs.