Behavioral Responses of Thrips (Thysanoptera: Thripidae) and Tarnished Plant Bug (Hemiptera: Miridae) to a New Bt Toxin, Cry51Aa2.834_16 in Cotton

Abstract Thrips (Thysanoptera: Thripidae) and tarnished plant bug, Lygus lineolaris (Hemiptera: Miridae), are among the most important insect pests of cotton, Gosssypium hirsutum, in the mid-southern United States. These pests are currently managed primarily by insecticides; however, a new Bt toxin, Cry51Aa2.834_16 is under evaluation for control of thrips and tarnished plant bug. Experiments were conducted to evaluate the behavioral response of thrips and tarnished plant bug to Bt Cry51Aa2.834_16. Adult thrips avoided Bt Cry51Aa2.834_16 cotton in field choice tests and in separate field tests of Bt and non-Bt cotton not treated with insecticides. In a greenhouse choice test, approximately twice as many adult thrips and eggs were found on non-Bt compared with Bt Cry51Aa2.834_16 cotton. Similarly, in a field test of nontreated Bt Cry51Aa2.834_16 and non-Bt cotton, 68% of adult thrips collected were found on non-Bt cotton. In cotton that was not sprayed with insecticides, Bt Cry51Aa2.834_16 did not affect the distribution of tarnished plant bug within the canopy, although more square and flower injury was caused by tarnished plant bug in non-Bt cotton. Adult tarnished plant bug exhibited a nonpreference for diet containing lyophilized Bt Cry51Aa2.834_16 leaves and for excised Bt Cry51Aa2.834_16 squares in choice tests with non-Bt squares. The behavioral responses of these pests when exposed to this new Bt toxin will play a key role in the efficacy and potential resistance management strategies if this new technology is incorporated in an overall cotton insect pest management system.

Download Full-text

Hydrogels: From Controlled Release to a New Bait Delivery for Insect Pest Management

Journal of Economic Entomology ◽

10.1093/jee/toaa183 ◽

2020 ◽

Vol 113 (5) ◽

pp. 2061-2068

Author(s):

Jia-Wei Tay ◽

Dong-Hwan Choe ◽

Ashok Mulchandani ◽

Michael K Rust

Keyword(s):

Controlled Release ◽

Pest Management ◽

Insect Pests ◽

Insect Pest ◽

Management Strategies ◽

Future Research ◽

Insect Pest Management ◽

Release Formulation ◽

The Past ◽

Minimal Environmental Impact

Abstract Here, we review the literature on the development and application of hydrogel compounds for insect pest management. Researchers have used hydrogel compounds for the past few decades to achieve the controlled release of various contact insecticides, but in recent years, hydrogel compounds have also been used to absorb and deliver targeted concentrations of toxicants within a liquid bait to manage insect pests. The highly absorbent hydrogel acts as a controlled-release formulation that keeps the liquid bait available and palatable to the target pests. This review discusses the use of various types of hydrogel compounds in pest management based on different environmental settings (e.g., agricultural, urban, and natural areas), pest systems (e.g., different taxa), and modes of insecticide delivery (e.g., spray vs bait). Due to their unique physicochemical properties, hydrogel compounds have great potential to be developed into new and efficacious pest management strategies with minimal environmental impact. We will also discuss the future research and development of hydrogels in this review.

Download Full-text

Host Plant Resistance to Leafminers in Lettuce

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.129.3.0383 ◽

2004 ◽

Vol 129 (3) ◽

pp. 383-388 ◽

Cited By ~ 9

Author(s):

Beiquan Mou ◽

Yong-Biao Liu

Keyword(s):

Insect Pest ◽

Choice Test ◽

Agricultural Crops ◽

Unit Leaf ◽

Lactuca Serriola ◽

Choice Tests ◽

Highly Correlated ◽

Leaf Lettuce ◽

Resistant Genotypes ◽

Cage Test

Leafminer (Liriomyza spp.) is a major insect pest of many important agricultural crops including lettuce (Lactuca sativa L.). The goals of this study were to evaluate lettuce genotypes for resistance to leafminers and to estimate the heritabilities of leafminer-resistant traits in the field, to examine the association among different resistant traits, and to study the mechanism of leafminer resistance in lettuce. Seventy-eight lettuce accessions and 232 F2 plants of crosses were evaluated for leafminer stings and the production of pupae and flies in the field in 2001 and 2002, and resistant genotypes were subjected to no-choice test. Wild species (Lactuca serriola L., L. saligna L., and L. virosa L.) had significantly fewer stings than cultivated lettuces. Among cultivated lettuces, sting densities were lowest on leaf lettuce and highest on romaine types. The sting results from the field were highly correlated with the results from insect cages (r = 0.770 and 0.756 for 2001 and 2002 tests, respectively), suggesting that a cage test can be used to screen for resistance in the field. Broad-sense heritability estimates for stings per unit leaf area in the field were 81.6% and 67.4% for 2001 and 2002 tests, respectively. The number of pupae produced per plant or per leaf was moderately correlated with sting density but was not correlated with leaf weight. Results suggest that both antixenosis and antibiosis exist in lettuce germplasm and resistant genotypes from choice tests remain resistant under no-choice conditions. These findings suggest that genetic improvement of cultivated lettuce for leafminer resistance is feasible.

Download Full-text

Pink Bollworm Resistance to Bt Toxin Cry1Ac Associated with an Insertion in Cadherin Exon 20

Toxins ◽

10.3390/toxins11040186 ◽

2019 ◽

Vol 11 (4) ◽

pp. 186 ◽

Cited By ~ 10

Author(s):

Ling Wang ◽

Yuemin Ma ◽

Xueqin Guo ◽

Peng Wan ◽

Kaiyu Liu ◽

...

Keyword(s):

Insect Pests ◽

Stop Codon ◽

Premature Stop Codon ◽

Pink Bollworm ◽

Cross Resistance ◽

Bt Cotton ◽

Wild Type ◽

Bt Toxin ◽

Exon 20 ◽

In Cells

Insecticidal proteins from Bacillus thuringiensis (Bt) are widely used to control insect pests, but their efficacy is reduced when pests evolve resistance. We report on a novel allele (r16) of the cadherin gene (PgCad1) in pink bollworm (Pectinophora gossypiella) associated with resistance to Bt toxin Cry1Ac, which is produced by transgenic cotton. The r16 allele isolated from a field population in China has 1545 base pairs of a degenerate transposon inserted in exon 20 of PgCad1, which generates a mis-spliced transcript containing a premature stop codon. A strain homozygous for r16 had 300-fold resistance to Cry1Ac, 2.6-fold cross-resistance to Cry2Ab, and completed its life cycle on transgenic Bt cotton producing Cry1Ac. Inheritance of Cry1Ac resistance was recessive and tightly linked with r16. Compared with transfected insect cells expressing wild-type PgCad1, cells expressing r16 were less susceptible to Cry1Ac. Recombinant cadherin protein was transported to the cell membrane in cells transfected with the wild-type PgCad1 allele, but not in cells transfected with r16. Cadherin occurred on brush border membrane vesicles (BBMVs) in the midgut of susceptible larvae, but not resistant larvae. These results imply that the r16 allele mediates Cry1Ac resistance in pink bollworm by interfering with the localization of cadherin.

Download Full-text

Variation in the spatio-temporal expression of insecticidal genes in cotton

Czech Journal of Genetics and Plant Breeding ◽

10.17221/131/2010-cjgpb ◽

2011 ◽

Vol 47 (No. 1) ◽

pp. 1-9 ◽

Cited By ~ 5

Author(s):

A. Bakhsh ◽

K. Shahzad ◽

T. Husnain

Keyword(s):

Environmental Factors ◽

Insect Pests ◽

Protein Biosynthesis ◽

Management Strategies ◽

Resistance Management ◽

Plant Biotechnology ◽

Transgenic Cotton ◽

Bt Cotton ◽

Temporal Expression ◽

Spatio Temporal

The most significant breakthrough in plant biotechnology is the development of the techniques to transform genes from unrelated sources into commercially important crop plants to develop resistance against targeted insect pests. The spatio-temporal expression of insecticidal genes in transgenic cotton varies with plant age, plant parts and environmental conditions. The understanding of this temporal and spatial variation in efficacy and the resulting mechanisms is essential for cotton protection and production. This review summarizes variations in the efficacy of introduced insecticidal genes in cotton crop. The factors contributing to the variability of endotoxins have also been highlighted. The reduction in Bt protein biosynthesis in late-season cotton tissues could be attributed to the overexpression of the Bt gene at earlier stages, which leads to gene regulation at post-transcription levels and consequently results in gene silencing at a later stage. Methylation of the promoter may also play a role in the declined expression of endotoxin proteins. In genetically modified crops several environmental factors have been reported to affect the expression of transgenes. Among environmental factors nitrogen metabolism, inhibition of synthesis, degradation, remobilization and high temperature are attributable to the quantitative reduction in Bt proteins. Applying plant growth regulators or protein enhancers such as Chaperone<sup>TM</sup> may improve Bt cotton efficacy through enhancing the synthesis of proteins. Also some agronomic practices such as nitrogen fertilization and timely irrigation favour the endotoxin expression. Thus, variations in the efficacy of insecticidal genes in transgenic cotton and the involved mechanisms need to be understood fully so as to plan rational resistance management strategies to retard the rate of resistance development and to control target pests effectively by enhancing the endotoxin expression through genetic or agronomic management.

Download Full-text

Farmer Knowledge of Climate Change Impacts and Adaptation Strategies in the Management of Vegetable Insect Pests in Zimbabwe

Journal of Agricultural Science ◽

10.5539/jas.v9n12p194 ◽

2017 ◽

Vol 9 (12) ◽

pp. 194

Author(s):

Rumbidzai Debra Katsaruware-Chapoto ◽

Paramu L. Mafongoya ◽

Augustine Gubba

Keyword(s):

Climate Change ◽

Elevated Temperatures ◽

Insect Pests ◽

Insect Pest ◽

Management Strategies ◽

Climate Change Impacts ◽

Effective Control ◽

Vegetable Production ◽

Farmer Knowledge ◽

Climate Change Risk

Farmer knowledge of insect pests’ risks in a changing climate is important in managing insect pests’ incidence. A total of 250 vegetable farmers from 5 wards in Zimbabwe were sampled using a semi-structured questionnaire to assess their knowledge on climate change risk, its impact on vegetable insects pests and management strategies to reduce the increased incidence of insect pests. Focus group discussions, key informant interviews and field observations were also used. Droughts and elevated temperatures were perceived to have the greatest impact on vegetable insect pests resulting in their increased incidence. Aphids, cutworms and whiteflies were identified among the major pests that have increased. The majority (53%) of the farmers cited high vegetable losses from insect pests attack. All the respondents (100%) revealed the use of chemical insecticides during production of vegetables. A higher proportion (60%) perceived effective control, 34% perceived reduced efficacy and 6% were not sure of effectiveness of chemical insecticides. Management strategies to cope with the increasing insect pests and diseases on vegetable production also included planting insect resistant cultivars, certified seeds, increased frequency of application of synthetic insecticides, insecticide mixtures, use of more hazardous chemical insecticides and increasing the rates of application resulting in insecticide overuse. There is need for government to facilitate development and adoption of Integrated Insect Pest Management (IIPM) and raise awareness on avoiding overdependence on chemical insecticides. Modelling tools that support adaptation planning needs to be developed to forecast climate change risk and the resultant incidence of insect pests.

Download Full-text

Nanopesticides: A Systematic Review of Their Prospects With Special Reference to Tea Pest Management

Frontiers in Nutrition ◽

10.3389/fnut.2021.686131 ◽

2021 ◽

Vol 8 ◽

Author(s):

Bhabesh Deka ◽

Azariah Babu ◽

Chittaranjan Baruah ◽

Manash Barthakur

Keyword(s):

Pest Management ◽

Insect Pests ◽

Plant Protection ◽

Insect Pest ◽

Management Strategies ◽

Crop Protection ◽

Tea Plant ◽

Research Field ◽

Active Ingredients ◽

The Impact

Background: Tea is a natural beverage made from the tender leaves of the tea plant (Camellia sinensis Kuntze). Being of a perennial and monoculture nature in terms of its cultivation system, it provides a stable micro-climate for various insect pests, which cause substantial loss of crop. With the escalating cost of insect pest management and increasing concern about the adverse effects of the pesticide residues in manufactured tea, there is an urgent need to explore other avenues for pest management strategies.Aim: Integrated pest management (IPM) in tea invites an multidisciplinary approach owing to the high pest diversity in the perennial tea plantation system. In this review, we have highlighted current developments of nanotechnology for crop protection and the prospects of nanoparticles (NPs) in plant protection, emphasizing the control of different major pests of tea plantations.Methods: A literature search was performed using the ScienceDirect, Web of Science, Pubmed, and Google Scholar search engines with the following terms: nanotechnology, nanopesticides, tea, and insect pest. An article search concentrated on developments after 1988.Results: We have described the impact of various pests in tea production and innovative approaches on the use of various biosynthesized and syntheric nanopesticides against specific insect pest targets. Simultaneously, we have provided support for NP-based technology and their different categories that are currently employed for the management of pests in different agro-ecosystems. Besides the broad categories of active ingredients (AI) of synthetic insecticides, pheromones and natural resource-based molecules have pesticidal activity and can also be used with NPs as a carriers as alternatives to traditional pest control agents. Finally, the merits and demerits of incorporating NP-based nanopesticides are also illustrated.Conclusions: Nanopesticides for plant protection is an emerging research field, and it offers new methods to design active ingredients amid nanoscale dimensions. Nanopesticide-based formulations have a potential and bright future for the development of more effective and safer pesticide/biopesticides.

Download Full-text

A Review of Interactions between Insect Biological Control Agents and Semiochemicals

Insects ◽

10.3390/insects10120439 ◽

2019 ◽

Vol 10 (12) ◽

pp. 439 ◽

Cited By ~ 3

Author(s):

Anamika Sharma ◽

Ramandeep Kaur Sandhi ◽

Gadi V. P. Reddy

Keyword(s):

Biological Control ◽

Natural Enemies ◽

Insect Pests ◽

Insect Pest ◽

Management Strategies ◽

Microbial Pathogens ◽

Insect Pheromones ◽

Biological Control Agents ◽

Plant Host ◽

Trap Crops

Biological control agents and semiochemicals have become essential parts of the integrated pest management of insect pests over recent years, as the incorporation of semiochemicals with natural enemies and entomopathogenic microbials has gained significance. The potential of insect pheromones to attract natural enemies has mainly been established under laboratory conditions, while semiochemicals from plants have been used to attract and retain natural enemies in field conditions using strategies such as trap crops and the push–pull mechanism. The best-known semiochemicals are those used for parasitoids–insect pest–plant host systems. Semiochemicals can also aid in the successful dispersal of entomopathogenic microbials. The use of semiochemicals to disseminate microbial pathogens is still at the initial stage, especially for bacterial and viral entomopathogens. Future studies should focus on the integration of semiochemicals into management strategies for insects, for which several semiochemical compounds have already been studied. More effective formulations of microbial agents, such as granular formulations of entomopathogenic fungi (EPFs), along with bio-degradable trap materials, could improve this strategy. Furthermore, more studies to evaluate species-specific tactics may be needed, especially where more than one key pest is present.

Download Full-text

Evaluation of host susceptibility, preference and offspring performance of Zeugodacus cucurbitae (Coquillett) (Diptera: Tephritidae) on different hosts

International Journal of Tropical Insect Science ◽

10.1007/s42690-019-00056-z ◽

2019 ◽

Vol 40 (1) ◽

pp. 93-99

Author(s):

Muzammil Farooq ◽

Sangita Baig ◽

Sabyan Faris Honey ◽

Babar Ehsan Bajwa ◽

Fazlullah ◽

...

Keyword(s):

Free Choice ◽

Insect Pest ◽

Management Strategies ◽

Solanum Melongena ◽

Fruit Flies ◽

Host Susceptibility ◽

Choice Test ◽

Pupal Weight ◽

Vegetable Crops ◽

Offspring Performance

Abstract The melon fruit fly, Zeugodacus cucurbitae (Coquillett) is a quarantine insect pest worldwide and affects the vegetable quality through its direct feeding and indirectly by passing way for secondary pathogens. This study investigated the host susceptibility, preference and offspring performance of Z. cucurbitae under the laboratory conditions. Different vegetable hosts i.e., brinjal (Solanum melongena L.), bitter gourd (Momordica charantia L.), zucchini (Cucurbita pepo L.), bottle gourd (Lagenaria siceraria [Molina] Standley) and cucumber (Cucumis sativus L.) were tested under no choice and free choice tests. Results showed that C. sativus and C. pepo have highest number of visits/host and oviposition puncture/host. C. sativus showed highest pupal recovery and pupal weight in both only choice and free choice test. While, highest percentage of emergence and female off springs were observed in C. pepo under only choice and free choice scenarios. Furthermore, maximum deformities in progeny were observed in case of L. siceraria under both test case scenarios. The current study provides exploratory support that fruit flies respond differently to host species that co-exists in field under choice and no choice test. Further, hosts of advantage to fruit flies are adopted more. The host and choice preference of fruit flies have the influence on the pest management strategies for the vegetable crops.

Download Full-text

Feeding, oviposition and survival of Liriomyza trifolii (Diptera: Agromyzidae) on Bt and non-Bt cottons

Bulletin of Entomological Research ◽

10.1017/s0007485308006317 ◽

2008 ◽

Vol 99 (3) ◽

pp. 253-261 ◽

Cited By ~ 7

Author(s):

Z. Lei ◽

T.-X. Liu ◽

S.M. Greenberg

Keyword(s):

Field Conditions ◽

Choice Test ◽

Bt Cotton ◽

Liriomyza Trifolii ◽

Laboratory Conditions ◽

Choice Tests

AbstractThe effects of Bt transgenic cottons (Bt-I expressing cry1Ac and Bt-II expressing cry1Ab and cry2Ab or cry1Ab and cry1Fa) and non-Bt cottons on feeding, oviposition and longevity of adults, and development and survival of Liriomyza trifolii larvae were studied under laboratory conditions; and infestation on four Bt and two non-Bt cotton traits were investigated under field conditions. Laboratory choice and no-choice tests showed that L. trifolii adults were capable of distinguishing between Bt cottons and non-Bt cottons. In a choice test on younger plants (4–5 leaves), the adults were found more often and made more feeding punctures (FP) on non-Bt cottons than on Bt cottons. On older plants (8–9 leaves), adults made the most FP on non-Bt cotton followed by those on Bt-II cottons and the least on Bt-I cotton. The females oviposited more eggs (6.7 eggs per leaf) on non-Bt cotton than on Bt-I (1.7 eggs per leaf) and Bt-II (0.8 eggs per leaf) cottons on younger plants and oviposited similar numbers of eggs (0.7–1.3 eggs per leaf) on non-Bt and Bt cottons on older plants. In a no-choice test, the females also fed more FP on non-Bt cottons than on Bt cottons on both younger and older plants. The females oviposited more eggs (15.6 eggs per leaf) on non-Bt cotton than on Bt-I (8.2 eggs per leaf) and Bt-II (6.5 eggs per leaf) cottons on younger plants and similar numbers of eggs (2.5–3.3 eggs per leaf) on non-Bt and Bt cottons on older plants. Larval and puparial survivals were not different among Bt and non-Bt cottons. The occurrence and damage of leafminers on cottons in the field showed that L. trifolii infested more plants and leaves and had more mines on non-Bt cotton than on Bt cottons.

Download Full-text