Relative Toxicity of Two Aphicides toHippodamia convergens(Coleoptera: Coccinellidae): Implications for Integrated Management of Sugarcane Aphid,Melanaphis sacchari(Hemiptera: Aphididae)

2016 ◽  
pp. tow265 ◽  
Author(s):  
Felipe Colares ◽  
J.P. Michaud ◽  
Clint L. Bain ◽  
Jorge B. Torres
2020 ◽  
Vol 113 (4) ◽  
pp. 1850-1857
Author(s):  
B E Wilson ◽  
F P F Reay-Jones ◽  
L Lama ◽  
M Mulcahy ◽  
T E Reagan ◽  
...  

Abstract The sugarcane aphid, Melanaphis sacchari Zehntner, is an economically damaging pest of sorghum, Sorghum bicolor (L.), across the southern United States. Field experiments investigated impacts of sorghum cultivar, nitrogen fertilization, and insecticides on M. sacchari infestations and sorghum yields in Louisiana and South Carolina in 2017 and 2018. In South Carolina, M. sacchari densities in unprotected plots peaked on 30–31 July of both years before declining by early- to mid-August. In Louisiana, infestations peaked on 26 and 12 July for 2017 and 2018, respectively, and declined by mid-August. Nitrogen fertilization influenced M. sacchari densities in Louisiana in 2018 with the highest-level infestations recorded from plots that received high N rates. Densities of M. sacchari on susceptible sorghum cultivar, DKS 38-88, were 1.5- to 2.3-fold greater than on DKS 37-07 in both years in Louisiana and in 2018 in South Carolina. Nitrogen fertilization was associated with improved sorghum yields in Louisiana experiments. Sorghum yields across experiments were 2- to 4-fold greater in plots protected with multiple insecticide applications than in unprotected plots. Yield from plots with insecticides sprayed once at currently used action thresholds differed from unprotected plots only in the 2018 Louisiana experiment. Results from these experiments indicate insecticidal protection of susceptible sorghum cultivars remains critical throughout much of the southern United States. Further research is needed to develop integrated management programs that incorporate fertilization manipulation, cultivar resistance, and insecticidal control.


2021 ◽  
Vol 22 (13) ◽  
pp. 7129
Author(s):  
Desalegn D. Serba ◽  
Xiaoxi Meng ◽  
James Schnable ◽  
Elfadil Bashir ◽  
J. P. Michaud ◽  
...  

The sugarcane aphid, Melanaphis sacchari (Zehntner) (Hemiptera: Aphididae) (SCA), has become a major pest of grain sorghum since its appearance in the USA. Several grain sorghum parental lines are moderately resistant to the SCA. However, the molecular and genetic mechanisms underlying this resistance are poorly understood, which has constrained breeding for improved resistance. RNA-Seq was used to conduct transcriptomics analysis on a moderately resistant genotype (TAM428) and a susceptible genotype (Tx2737) to elucidate the molecular mechanisms underlying resistance. Differential expression analysis revealed differences in transcriptomic profile between the two genotypes at multiple time points after infestation by SCA. Six gene clusters had differential expression during SCA infestation. Gene ontology enrichment and cluster analysis of genes differentially expressed after SCA infestation revealed consistent upregulation of genes controlling protein and lipid binding, cellular catabolic processes, transcription initiation, and autophagy in the resistant genotype. Genes regulating responses to external stimuli and stress, cell communication, and transferase activities, were all upregulated in later stages of infestation. On the other hand, expression of genes controlling cell cycle and nuclear division were reduced after SCA infestation in the resistant genotype. These results indicate that different classes of genes, including stress response genes and transcription factors, are responsible for countering the physiological effects of SCA infestation in resistant sorghum plants.


Author(s):  
Liliana Aguilar Marcelino ◽  
Jesús Antonio Pineda Alegría ◽  
David Osvaldo Salinas-Sánchez ◽  
Víctor Manuel Hernández Velázquez ◽  
Gonzalo Iván Silva Aguayo ◽  
...  

The sugarcane aphid, Melanaphis sacchari Zehntner (Hemiptera: Aphididae), is the main pest of sorghum, Sorghum bicolor L. Moench (Poaceae), in Mexico. To control this insect, farmers currently use synthetic chemical insecticides, which are toxic to humans and biodiversity. However, natural products are a promising potential source of safer alternative means to control different agricultural pests. The main objective of this study was to evaluate the insecticidal effect of contact by fumigation of pure molecules of four commercial fatty acids (palmitic, stearic, pentadecanoic and linoleic acids), the phytosterol ß -sitosterol, and the flavonoid rutin. The results showed that fatty acids were the most effective against M. sacchari ; the highest mortality rate (85%) was produced by linoleic acid and the LC 50 was 1,181 ppm, followed by stearic and palmitic acids with mortality percentages of 74 and 63%, respectively, at a concentration of 2,500 ppm at 72 h. The positive control, imidacloprid, had 100% mortality in 24 h and the tween 20 negative control exhibited 4% mortality in 72 h. Our results show that commercial fatty acids are effective against adults of M. sacchari , and can be considered an environmentally friendly alternative to the frequent use of synthetic chemical insecticides.


2020 ◽  
Vol 113 (4) ◽  
pp. 257-265 ◽  
Author(s):  
Jocelyn R Holt ◽  
Alex Styer ◽  
Jennifer A White ◽  
J Scott Armstrong ◽  
Samuel Nibouche ◽  
...  

Abstract The sugarcane aphid (SCA), Melanaphis Sacchari (Zehntner) (Hemiptera: Aphididae), has been considered an invasive pest of sugarcane in the continental United States since 1977. Then, in 2013, SCA abruptly became a serious pest of U.S. sorghum and is now a sorghum pest in 22 states across the continental United States. Changes in insect-associated microbial community composition are known to influence host-plant range in aphids. In this study, we assessed whether changes in microbiota composition may explain the SCA outbreak in U.S. sorghum. We characterized the SCA bacterial microbiota on sugarcane and grain sorghum in four U.S. states, using a metabarcoding approach. In addition, we used taxon-specific polymerase chain reaction (PCR) primers to screen for bacteria commonly reported in aphid species. As anticipated, all SCA harbored the primary aphid endosymbiont Buchnera aphidicola, an obligate mutualistic bacterial symbiont. Interestingly, none of the secondary symbionts, facultative bacteria typically associated with aphids (e.g., Arsenophonus, Hamiltonella, Regiella) were present in either the metabarcoding data or PCR screens (with the exception of Rickettsiella and Serratia, which were detected by metabarcoding at low abundances <1%). However, our metabarcoding detected bacteria not previously identified in aphids (Arcobacter, Bifidobacterium, Citrobacter). Lastly, we found microbial host-associated differentiation in aphids that seems to correspond to genetically distinct aphid lineages that prefer to feed on grain sorghum (MLL-F) versus sugarcane (MLL-D).


2019 ◽  
Vol 112 (6) ◽  
pp. 2731-2736 ◽  
Author(s):  
Nicholas J Seiter ◽  
Anne D Miskelley ◽  
Gus M Lorenz ◽  
Neelendra K Joshi ◽  
Glenn E Studebaker ◽  
...  

Abstract The sugarcane aphid, Melanaphis sacchari (Zehntner) (Hemiptera: Aphididae), has become a major pest of grain sorghum, Sorghum bicolor (L.) Moench, in the United States in recent years. Feeding by large densities of sugarcane aphids causes severe damage, which can lead to a total loss of yield in extreme cases. Our objective was to determine the effect of grain sorghum planting date on sugarcane aphid population dynamics and their potential to reduce yields. We conducted field experiments from 2015 to 2017 in which an aphid-susceptible grain sorghum hybrid was planted at four different dates, which encompassed the typical range of planting dates used in Arkansas production systems. Plots were either protected from sugarcane aphid feeding using foliar insecticide sprays, or left untreated to allow natural populations of sugarcane aphids to colonize and reproduce freely. Planting date impacted both the magnitude and severity of sugarcane aphid infestations, with the highest population densities (and subsequent reductions in sorghum yield) generally occurring on plots that were planted in May or June. Sugarcane aphid feeding reduced yields in the untreated plots in two of the four planting date categories we tested. Earlier planting generally resulted in less sugarcane aphid damage and improved yields compared with later planting dates. While the effect of planting date on sugarcane aphid populations is likely to vary by region, sorghum producers should consider grain sorghum planting date as a potential cultural tactic to reduce the impact of sugarcane aphid.


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