Vegetable production in the Southeast is always at high risk from insect pests. Alternative integrated pest management (IPM) systems have to be effective in small plot as well as at the farming scale.This article explores the recent studies on large-scale trap crops using single or multiple cultivars and innovative layouts for long-term pest reduction. Trap crops must be planned carefully under high pest pressure and drought conditions along with an insecticide use strategy that minimizes external inputs and conserves natural enemies. Through participatory research approach, trap crop systems continue to evolve into practical solutions for the vegetable producers.

Habitat management is an important strategy for pest control in integrated pest management (IPM). Various categories of habitat management such as trap cropping, intercropping, natural enemy refuges such as ‘beetle banks’, and floral resources for parasitoids and predators, have been used in applied insect ecology for many years. In a broader sense, two mechanisms, the ‘enemies hypothesis' and the ‘resource concentration hypothesis' have been identified as acting independently or combined in pest population dynamics. The ‘enemies hypothesis' directly supports the conservation and enhancement of natural enemies, floral resources such as shelter, nectar, alternative food sources, and pollen (SNAP) to improve conservation biological control. The ‘resource concentration hypothesis’ emphasizes how the host selection behavior of herbivores in a diverse habitat can reduce pest colonization in crops. This review emphasizes the potential of these approaches, as well as possible dis-services, and includes limitations and considerations needed to boost the efficacy of these strategies worldwide.

This paper reviews the most important cases of trap crops and insectary plants in the order Brassicales. Most trap crops in the order Brassicales target insects that are specialist in plants belonging to this order, such as the diamondback moth, Plutella xylostella L. (Lepidoptera: Plutellidae), the pollen beetle, Meligethes aeneus Fabricius (Coleoptera: Nitidulidae), and flea beetles in the genera Phyllotreta and Psylliodes (Coleoptera: Chrysomelidae). In most cases, the mode of action of these trap crops is the preferential attraction of the insect pest for the trap crop located next to the main crop. With one exception, these trap crops in the order Brassicales have been used with brassicaceous crops. Insectary plants in the order Brassicales attract a wide variety of natural enemies, but most studies focus on their effect on aphidofagous hoverflies and parasitoids. The parasitoids benefiting from insectary plants in the order Brassicales target insects pests ranging from specialists, such as P. xylostella, to highly polyfagous, such as the stink bugs Euschistus conspersus Uhler and Thyanta pallidovirens Stål (Hemiptera: Pentatomidae). In the order Brassicales, the three most common trap crops are Indian mustard, Brassica juncea (L.) Czern, Chinese cabbage, Brassica rapa L., and yellow rocket, Barbarea vulgaris R. Br., while the three most common insectary plants are sweet alyssum, Lobularia maritima (L.) Desv., white mustard, Sinapis alba L, and B. vulgaris. Except for Tropaeolum majus L. (Tropaeolaceae) and Capparis decidua (Forssk.) Edgew. (Capparaceae), the tested trap crops and insectary plants in the order Brassicales belong to the family Brassicaceae.

Trap crops are plants grown along with the main crop in order to manipulate insect behavior to manage the insect pests and are used as a cultural management strategy in several crops. Trap crops also provide habitat to natural enemies and can reduce the need for insecticides and hence reduce the development of insecticide resistance. The attractiveness of the trap crop, the timing of planting, and the space it occupies are major factors to consider before selecting and using a trap crop. The addition of semiochemicals and incorporation of ‘stimulo-deterrent diversion’ can increase the efficiency of trap crops. The important insect pests of cereal crops reported to managed by using trap crops include the wheat stem sawfly, Cephus cinctus Norton (Hymenoptera: Cephidae), on wheat and the stem borers Chilo partellus (Swinhoe) and Busseola fusca (Fuller) on maize and sorghum. Other insect pests such as soil-dwelling wireworms [Agriotes obscurus L., Limonius californicus (Mannerheim) (Coleoptera: Elateridae)] on potatoes and the aphids Schizaphis graminum (Rondani) (Hemiptera: Aphididae), and Rhopalosiphum padi L. on wheat and the brown planthopper Nilaparvata lugens (Stål) on rice are also possible to manage by using trap crops. Cereal crops such as maize and wheat are sometimes themselves used as trap crops, yet there have been only a handful of attempts made to use trap crops in cereal crops. The major limiting factors in using trap crops in cereal crops are environmental conditions, variation in landscape and cultivation practices. Nonetheless, trap crops remain an important tool of integrated pest management, and future studies should work to improve the efficacy, cost efficiency, and availability of alternative trap crops for use in cereal cultivation.

Cultural methods are some of the most widely adopted approaches in integrated pest management. Trap cropping is based on the principle of using a relatively more preferred crop species to keep the pest away from the main crop and reduce pest damage.This technique has tremendous potential to keep the pest below the economic damage threshold and can be used for pest management in organic farming. Furthermore, trap crops can be linked to habitat management and conservation biological control to improve multiple ecosystem services in an agroecosystem. While trap cropping is one of the most common cultural pest management control methods in subsistence farming in South Asia, it has not yet become common in conventional agriculture, nor has this practice been well documented in this region. This work broadly reviews the most relevant literature related to trap cropping used in pest management in this region. Regional cooperation for knowledge-sharing and research collaborations, motivating farmers to promote organic farming, along with increased research and policy interventions to favor sustainable agriculture have been done to promote this pest management practice in South Asia.

Tea is an economically important crop, consumed by billions of people. Despite the increasing market for pesticide-free products, the use of pesticide in tea is still high. In order to investigate whether intercropping promotes biological control organisms, Chamaecrista rotundifolia (Pers.) Greene, Indigofera hendecaphylla Jacq., Trifolium repens L., and Vigna sinensis (L.) were separately intercropped with free weeding as control in a tea plantation at Yangli, China. Arthropods were collected by taking sweep-net samples, and treatment effects on assemblages were investigated. The combined species richness of all arthropods and that of parasitoids was significantly increased in intercropped treatments while the species richness of herbivores and predators was only greater in C. rotundifolia and I. hendecaphylla intercropped treatments. Compared with control, the combined abundance of all arthropods, and that of herbivores was lower, while the abundance of parasitoids and its taxa was greater in all intercropped treatments. The abundance of predators and its taxa was greater only in tea plantations intercropped with C. rotundifolia or I. hendecaphylla. Of the herbivores, the abundance of Empoasca onukii Matsuda, Sternorrhyncha, Aleyrodidae, and Pentatomidae was greater in the areas intercropped with C. rotundifolia in comparison with the control, but the abundance of Thysanoptera and Geometridae caterpillars was lower.The recorded increase in the abundance of beneficial arthropods may explain the lower abundance of Thysanoptera or Geometridae caterpillars detected in the intercropped tea plantations. Our results indicate that intercropping has the potential to enhance arthropod biodiversity, and to provide an option for sustainable pest control in tea plantations.

Increasing habitat complexity through cover cropping has been proposed as a tactic to reduce herbivore colonization and encourage natural enemies in cropping systems. To test the supposition that cover crops can be used to alter arthropod communities, we compared arthropod communities on cucumber (Cucumis sativus L.; Cucurbitaceae) interplanted with a red clover (Trifolium pratense L.; Fabaceae) living mulch and grown as a monoculture. In 2016 and 2017, visual surveys and yellow sticky card traps were used to estimate numbers of arthropod natural enemies and herbivores in each treatment. Among herbivores, striped cucumber beetles [Acalymma vittatum (Fabricius, 1775); Coleoptera: Chrysomelidae] and melon aphids (Aphis gossypii Glover, 1877; Hemiptera: Aphididae) had lower densities in the presence of red clover. However, populations of spotted cucumber beetle (Diabrotica undecimpunctata howardi Barber, 1947; Coleoptera: Chrysomelidae) had a variable response to red clover. Sticky card captures of natural enemies, including bigeyed bugs (Geocoris spp. Fallén; Hemiptera: Geocoridae), minute pirate bugs (Orius spp. Wolff; Hemiptera: Anthocoridae), and lady beetles (Coleoptera: Coccinellidae), were generally greater in cucumber interplanted with red clover than monoculture. Overall, cucumber yield did not differ between treatments. Findings from this study lend support to the hypothesis that greater habitat complexity can reduce herbivore densities.

One complementary or alternative control measure to chemical insecticide is interplanting of plants that affect insect behavior. While few successes are known based on interplanting of different varieties of the same crop, such intra-crop interplanting may be effective against insects that feed on a limited range of plants and have persistent preference to one cultivar. Here, we report three field trials that examined the efficacy of intra-crop interplanting of sweet potato varieties, Ipomoea batatas (L.) Lamarck (Solanales: Convolvulaceae), on an oligophagous weevil, Euscepes postfasciatus (Fairmaire) (Coleoptera: Curculionidae), planting a preferred variety, Beni-masari, together with a less preferred one, Kyushu 166. In the first experiment, Beni-masari was planted as a border around Kyushu 166 and this arrangement decreased tuber damage in the main crop (Kyushu 166), although damage reduction was not statistically significant from monoculture plantings of Kyushu 166. In the second experiment, both varieties were planted in plots spaced 3 m apart to test the attractiveness of Beni-masari to weevils from Kyushu 166. No attractive effects of Beni-masari were observed. In the third experiment, the two varieties were planted in separate plots that were contiguous to each other, and in this experiment Beni-masari preferentially attracted weevils away from Kyushu 166 within 3 m distance, and tuber damage in Kyushu 166 within that zone was reduced owing to the attractiveness of Beni-masari. We discuss the potential of the intra-crop interplanting in pest management.

In total, 107 colonies of the cryptic ant Proceratium itoi (Forel) were collected from an evergreen broad-leaved forest in central Japan.Their nests were excavated directly from the soil at depths of 10–15 cm. Most colonies were monogynous and colony sizes were small; the median and maximum numbers of workers per colony were 35 and 253, respectively. The ant nests collected during May–September frequently contained many arthropod eggs; thus, the ants are likely to be specialized for predation on these eggs. Hatchlings from the eggs were identified as species belonging to Chilopoda, Hemiptera, and Opiliones. Other species of Proceratium have long been presumed, without evidence, to prey on spider eggs; however, no spider eggs were found among approximately 1,800 prey eggs present in P. itoi nests.

The Asian citrus psyllid, Diaphorina citri Kuwayama, is native to Asia but has recently invaded North America. Asian citrus psyllid is a significant pest of citrus crops by its direct feeding but, more importantly, as the vector of the bacterium ‘Candidatus Liberibacter asiaticus’, which causes Huanglongbing disease. Asian citrus psyllid was first found in México in 2001 and 2002 and, since then, has spread quickly across the country, suggesting rapid adaptation to new environments. Yet, we lack information on the genetic variation and structure that could facilitate or inhibit adaptation. Using six microsatellite markers, we analyzed genetic variation and structure among six localities in México: three in western states near the Pacific coast and two in the Yucatán Peninsula near the Gulf of México. We found low genetic diversity (no more than three alleles per locus) and intermediate differentiation between all populations. Asian citrus psyllid populations clustered into two genetic groups, but, surprisingly, these clusters were present in western populations. The first group included El Arenal, and the second group included Autlán de Navarro, Colima, and Tecomán. Interestingly, both of the Yucatán populations shared variation from the two clusters, suggesting admixture. We infer that reproductive isolation, barriers to gene flow, local selection, and the possibility of multiple invasions have influenced the current genetic structure of Asian citrus psyllid in México.

The Old World bollworm, Helicoverpa armigera (Hübner), is one of the most destructive agricultural pests worldwide. It was first recorded in Brazil in 2013, yet despite this recent introduction, H. armigera has spread throughout much of Latin America. Where H. armigera has become established, it is displacing or hybridizing with the congeneric New World pest Helicoverpa zea. In addition to the adaptive qualities that make H. armigera a megapest, such as broad range pesticide resistance, the spread of H. armigera in the New World may have been hastened by multiple introductions into South America and/or the Caribbean. The recent expansion of the range of H. armigera into the New World is analyzed herein using mtDNA of samples from South America, the Caribbean Basin, and the Florida Peninsula. Phylogeographic analyses reveal that several haplotypes are nearly ubiquitous throughout the New World and native range of H. armigera, but several haplotypes have limited geographic distribution from which a secondary introduction with Euro-African origins into the New World is inferred. In addition, host–haplotype correlations were analyzed to see whether haplotypes might be restricted to certain crops. No specialization was found; however, some haplotypes had a broader host range than others. These results suggest that the dispersal of H. armigera in the New World is occurring from both natural migration and human-mediated introductions. As such, both means of introduction should be monitored to prevent the spread of H. armigera into areas such as the United States, Mexico, and Canada, where it is not yet established.

Predators affect prey through direct consumption as well as by inducing prey to defensively alter their phenotypes, including behavioral phenotypes, to maximize survival under predation risk. Closely related sympatric prey species with shared natural enemies may resolve behavioral trade-offs under predation risk differently. In a laboratory experiment, we investigated two co-occurring semiaquatic backswimmer congeners, which exhibit differences in their degree of habitat specialization across a gradient of habitat permanence. Notonecta irrorata Uhler primarily occur in ephemeral ponds, whereas Notonecta undulata Say are habitat generalists that are commonly found in both permanent and ephemeral ponds.We tested whether the two species differed in antipredator responses to both visual and chemical cues of a shared predator, the giant water bug, in a fully factorial design.The generalist species, N. undulata, exhibited reductions in activity in the presence of predator chemical cues only, whereas the specialist species, N. irrorata, remained consistently active across predator cue treatments. Our work shows that there are species-specific differences in how prey assess or respond to predation risk.The varying propensities of these backswimmer congeners to behaviorally respond to a shared predator, and differences in their behavior when exposed to different predation risk cues may be linked to underlying divergence in their life-history strategies.

In this study, we carried out an inventory of butterfly diversity and an analysis of alpha and beta diversity considering the effects of phenology and degree of disturbance in tropical dry forest. The study included three localities: Cañadas de Ajuchitlán and El Limón, situated within the Sierra de Huautla Biosphere Reserve (REBIOSH) natural protected area, and San Miguel de los Elotes, which is outside of the REBIOSH. We systematically sampled each of the localities using two collection methods once per month for a full year (April 2013 to March 2014). A total of 4,017 specimens belonging to 119 species and 83 genera were collected. We recorded for the first time the presence of Perichares aurina Evans (Lepidoptera, Hesperiidae), in Mexico, 14 additional Hesperiidae species were new records for Morelos, Mexico, and 16% of the species recorded in this study are endemic to Mexico. Species richness was highest in August for the two localities (Cañadas de Ajuchitlán and El Limón), located within the REBIOSH. Species richness was highest in November for San Miguel de los Elotes, which is outside of the REBIOSH. In terms of the alpha diversity values (⁰D, observed diversity), Cañadas de Ajuchitlán had the highest species richness. In the analysis of similarity (Beta diversity), the two localities within the REBIOSH had the highest species similarity, despite being the most geographically distant.