Nitenpyram, Dinotefuran, and Thiamethoxam Used as Seed Treatments Act as Efficient Controls against Aphis gossypii via High Residues in Cotton Leaves

The effects of eight neonicotinoid seed treatments against the cotton aphid Aphis gossypii and its natural enemies in Bt cotton fields were evaluated, and the concentrations of these neonicotinoids in cotton leaves and soil were also investigated. The results showed that all neonicotinoid seed treatments efficiently reduced A. gossypii populations throughout the cotton seedling stage. The percentages of curly leaf plants in all of the neonicotinoid seed treatments were below the threshold for economic loss. Among the eight tested neonicotinoid seed treatments, nitenpyram, dinotefuran, and thiamethoxam showed high control efficiency against A. gossypii. Residues of the three neonicotinoids were higher than those of other neonicotinoids in cotton leaves. Moreover, residues of dinotefuran and nitenpyram remained at low levels in the soil. However, the abundance of natural enemies in the cotton field was to some extent influenced by neonicotinoid seed treatments. Therefore, neonicotinoids nitenpyram, dinotefuran, and thiamethoxam used as seed treatment can provide effective protection that should play an important role in the management of early-season A. gossypii in Bt cotton fields; however, the risks of neonicotinoids to the environment should also be considered

Seed Treatment Combined with a Spot Application of Clothianidin Granules Prolongs the Efficacy of Controlling Piercing–Sucking Insect Pests in Cotton Fields

Seed treatments can directly protect cotton from early season piercing–sucking insect Aphis gossypii Glover but hardly provide long-term protection against Apolygus lucorum (Meyer-Dür). Therefore, the efficacy of clothianidin seed treatments combined with spot applications of clothianidin granules at the bud stage of cotton was evaluated to control piercing–sucking pests during the entire cotton growing season. Clothianidin seed treatments (at the rate of 4 g ai/kg seed) combined with a clothianidin granular treatment (even at low rate of 0.9 kg ai/ha) at the bud stage can effectively suppress A. gossypii and A. lucorum infestations throughout the seedling and blooming stages after planting and can improve cotton yield. The spot application of clothianidin granules also reduced the population densities of Bemisia tabaci (Gennadius). The dynamic changes of clothianidin residues demonstrated that the control efficacy of clothianidin against A. gossypii and A. lucorum might be related to the residues of this neonicotinoid in cotton leaves. This pest management practice provided long-term protection against cotton piercing–sucking pests for the entire growing season of cotton plants and could supplement the short-term control efficiency of clothianidin used as a seed treatment

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<p>Bradysia odoriphaga is an agricultural pest insect affecting the production of Chinese chive and other liliaceous vegetables in China, and it is significantly attracted by sex pheromones and the volatiles derived from host plants. Despite verification of this chemosensory behavior, however, it is still unknown how B. odoriphaga recognizes these volatile compounds on the molecular level. Many of odorant binding proteins (OBPs) and chemosensory proteins (CSPs) play crucial roles in olfactory perception. Here, we identified 49 OBP and 5 CSP genes from the antennae and body transcriptomes of female and male adults of B. odoriphaga, respectively. Sequence alignment and phylogenetic analysis among Dipteran OBPs and CSPs were analyzed. The sex- and tissue-specific expression profiles of 54 putative chemosensory genes among different tissues were investigated by quantitative real-time PCR (qRT-PCR). qRT-PCR analysis results suggested that 22 OBP and 3 CSP genes were enriched in the antennae, indicating they might be essential for detection of general odorants and pheromones. Among these antennae-enriched genes, nine OBPs (BodoOBP2/4/6/8/12/13/20/28/33) were enriched in the male antennae and may play crucial roles in the detection of sex pheromones. Moreover, some OBP and CSP genes were enriched in non-antennae tissues, such as in the legs (BodoOBP3/9/19/21/34/35/38/39/45 and BodoCSP1), wings (BodoOBP17/30/32/37/44), abdomens and thoraxes (BodoOBP29/36), and heads (BodoOBP14/23/31 and BodoCSP2), suggesting that these genes might be involved in olfactory, gustatory, or other physiological processes. Our findings provide a starting point to facilitate functional research of these chemosensory genes in B. odoriphaga at the molecular level.</p

The sublethal effects of cyantraniliprole on the development and growth of <i>A</i>. <i>ipsilon</i>.

<p>The sublethal effects of cyantraniliprole on the development and growth of <i>A</i>. <i>ipsilon</i>.</p

The sublethal effects of cyantraniliprole on <i>A</i>. <i>ipsilon</i> parent population parameters.

<p>The sublethal effects of cyantraniliprole on <i>A</i>. <i>ipsilon</i> parent population parameters.</p

Feeding indices of fourth instar larvae of <i>A</i>. <i>ipsilon</i> after treatment with cyantraniliprole.

<p>Feeding indices of fourth instar larvae of <i>A</i>. <i>ipsilon</i> after treatment with cyantraniliprole.</p

Life expectancy (<i>e</i>_<i>xj</i>) of <i>A</i>. <i>ipsilon</i> exposed to sublethal concentrations of cyantraniliprole.

<p>Life expectancy (<i>e</i>_<i>xj</i>) of <i>A</i>. <i>ipsilon</i> exposed to sublethal concentrations of cyantraniliprole.</p

Toxicity of cyantraniliprole on the fourth instar larvae of <i>A</i>. <i>ipsilon</i>.

<p>Toxicity of cyantraniliprole on the fourth instar larvae of <i>A</i>. <i>ipsilon</i>.</p

Effects of Sublethal Concentrations of Cyantraniliprole on the Development, Fecundity and Nutritional Physiology of the Black Cutworm <i>Agrotis ipsilon</i> (Lepidoptera: Noctuidae) - Fig 1

<p>Pupae weight of male and female of <i>A</i>. <i>ipsilon</i> in parent population (a) and percentage of offspring eggs that hatched in the offspring population (b) after the parent fourth-instar larval stage was exposed to sublethal concentrations of cyantraniliprole. Bars labeled with the same letters do not differ significantly (a, 200,000 bootstraps; b, Student-Newman-Keuls test, <i>P</i>< 0.05).</p

Effects of Sublethal Concentrations of Cyantraniliprole on the Development, Fecundity and Nutritional Physiology of the Black Cutworm <i>Agrotis ipsilon</i> (Lepidoptera: Noctuidae) - Fig 6

<p>The amount of nutrients (a: carbohydrate, b: lipid, c: total protein) in fourth-instar larvae of <i>A</i>. <i>ipsilon</i> (Mean ± SE) after treatment with sublethal concentrations of cyantraniliprole. Bars labeled with the same letters do not differ significantly (Student-Newman-Keuls test, <i>P</i>< 0.05).</p