scholarly journals Monitoring Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) Infestation in Soybean by Proximal Sensing

Insects ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 47
Author(s):  
Pedro P. S. Barros ◽  
Inana X. Schutze ◽  
Fernando H. Iost Filho ◽  
Pedro T. Yamamoto ◽  
Peterson R. Fiorio ◽  
...  

Although monitoring insect pest populations in the fields is essential in crop management, it is still a laborious and sometimes ineffective process. Imprecise decision-making in an integrated pest management program may lead to ineffective control in infested areas or the excessive use of insecticides. In addition, high infestation levels may diminish the photosynthetic activity of soybean, reducing their development and yield. Therefore, we proposed that levels of infested soybean areas could be identified and classified in a field using hyperspectral proximal sensing. Thus, the goals of this study were to investigate and discriminate the reflectance characteristics of soybean non-infested and infested with Bemisia tabaci using hyperspectral sensing data. Therefore, cages were placed over soybean plants in a commercial field and artificial whitefly infestations were created. Later, samples of infested and non-infested soybean leaves were collected and transported to the laboratory to obtain the hyperspectral curves. The results allowed us to discriminate the different levels of infestation and to separate healthy from whitefly infested soybean leaves based on their reflectance. In conclusion, these results show that hyperspectral sensing can potentially be used to monitor whitefly populations in soybean fields.

Author(s):  
Pedro P. S. Barros ◽  
Inana X. Schutze ◽  
Fernando H. Iost Filho ◽  
Pedro Takao Yamamoto ◽  
Peterson Fiorio ◽  
...  

Although monitoring and observing insect pest populations in the fields is essential in crop management, it is still a laborious and sometimes ineffective process. High infestation levels may diminish the photosynthetic activity of soybean plants, affecting their development and reducing the yield. An imprecise decision making in integrated pest management program may lead to an ineffective control in infested areas or the excessive use of insecticides. In order to reach a more efficient control of arthropods population it is important to evaluate the infestation in time to mitigate its negative effects on the crop and remote sensing is an important tool for monitoring. It was proposed that infested soybean areas could be identified, and the arthropods quantified from non-infested areas in a field by hyperspectral remote sensing. Thus, the goals of this study were to investigate and discriminate the reflectance characteristics of soybean non-infested and infested with Bemisia tabaci using hyperspectral remote sensing data. Therefore, samples of infested and non-infested soybean leaves were collected and transported to the laboratory to obtain the hyperspectral curves. The results obtained allowed to discriminate the different levels of infestation and to separate healthy from whitefly infested soybean leaves based on their reflectance.


2019 ◽  
Vol 11 (2) ◽  
pp. 251
Author(s):  
Bruna Taiza Locateli ◽  
Mycheli Preuss da Cruz ◽  
Nean Locatelli Dalacosta ◽  
Karine Fuschter Oligine ◽  
Edson Bertoldo ◽  
...  

The whitefly, Bemisia tabaci Biotype B (Hemiptera: Aleyrodidae), is considered one of the world’s major agricultural pest groups, attacking a wide range of crop hosts and causing considerable crop loss. Understanding the interactions between whiteflies and host plants promotes the development of novel strategies for controlling whiteflies. This study aimed to evaluate the biochemical alterations caused by induced resistance in soybean plants, challenged by B. tabaci. The experiment was performed at the Federal University of Technology, Parana. Soybean seeds (cv. BRS 284) were sown in polyethylene pots in the greenhouse. The elicitors sprayed on the soybean leaves were: acibenzolar-S-Methyl (ASM-0.005%); Salicylic Acid (SA-2Mm); foliar phosphite (ULTRA K®-0.004%); Chitosan (CH-1%); and silicon (SI-0.25%); whilst the control group was sprayed with distilled water. Plants were infested with 50 adult whiteflies in the cages that were released after applying the treatments. At 0, 24, 48 and 96 hours after the beginning of the experiment, biochemical analyses of total proteins and the activity of the phenylalanine ammonia-lyase (PAL), peroxidases (PO), phenolic compounds, chitinase, and β-1,3-glucanase were made. The results showed that the application of elicitors increased the route of the phenylpropanoids with the activation of PAL and formation of phenolic compounds. It was also verified the activation of pathogenicity-related enzymes such as peroxidases and chitinase.


Author(s):  
Ran Wang ◽  
Yuan Hu ◽  
Peiling Wei ◽  
Cheng Qu ◽  
Chen Luo

Abstract Odorant binding proteins (OBPs) of insects play a critical role in chemical perceptions and choice of insect host plant. Bemisia tabaci is a notorious insect pest which can damage more than 600 plant species. In order to explore functions of OBPs in B. tabaci, here we investigated binding characteristics and function of odorant-binding protein 3 in B. tabaci (BtabOBP3). The results indicated that BtabOBP3 shows highly similar sequence with OBPs of other insects, including the typical signature motif of six cysteines. The recombinant BtabOBP3 protein was obtained, and the evaluation of binding affinities to tested volatiles of host plant was conducted, then the results indicated that β-ionone had significantly higher binding to BtabOBP3 among other tested plant volatiles. Furthermore, silencing of BtabOBP3 significantly altered choice behavior of B. tabaci to β-ionone. In conclusion, it has been demonstrated that BtabOBP3 exerts function as one carrier of β-ionone and the results could be contributed to reveal the mechanisms of choosing host plant in B. tabaci.


2021 ◽  
Vol 13 (10) ◽  
pp. 31
Author(s):  
Walquíria F. Teixeira ◽  
Evandro B. Fagan ◽  
Antônio P. M. Machado ◽  
Daniel Fortune ◽  
Fernando R. Moreira

Soybean is one of the world’s most economically important crops and several factors can affect the productivity of this culture. Among these factors is the supply of needed nitrogen, especially in the reproductive stage, as it acts in photosynthetic activity and in grain filling. In view of this, the objective of our work was to evaluate the effect of foliar application of nitrogen in different reproductive stages in soybean culture. Two sources of nitrogen were used: conventional urea and urea-formaldehyde/triazone, both applied in reproductive stages R2, R3, R4, or R5, as well as a control treatment without foliar application of nitrogen. Plants submitted to foliar application of urea-formaldehyde/triazone showed an increase in nitrogen metabolism (percentage of nitrogen derived from the atmosphere [Ndfa] and nitrate reductase activity [NR]), an increase in peroxidase (POD), and the consequent reduction in hydrogen peroxide (H2O2) in all stages of application of this treatment. When urea-formaldehyde/triazone was applied in R4, it resulted in a 7% increase in yield. The application of conventional urea in reproductive stages R4 and R5 increased nitrogen metabolism and resulted in an increase in yield by 4%. However, conventional urea reduced yield when applied in stages R2 and R3. The use of low doses of foliar nitrogen in stages R4 and R5, increased nitrogen metabolism in soybean plants. The timing of the application has a direct impact on the results with the slow-release nitrogen (urea formaldehyde /triazone) showing better results when applied in stage R4 and better results for conventional urea in R5.


EUGENIA ◽  
2015 ◽  
Vol 21 (1) ◽  
Author(s):  
J. Rimbing ◽  
J. Pelealu ◽  
D. Sualang

ABSTRACT   The research was arranged in a randomized block design (RBD), with 10 treatments and 3 replications. To get the active insects pests, net sweepings were done for the flying insects, while other pests were observed directly on the plants. Collecting data of plant damages were made by systematic diagonal lines, except for viruses, census was conducted on each experimental plot.  The results of this experiment documented 12 species of insect pests attacking soybean plants. Soybean pest populations were relatively low, except for Aphis glycine that was quite high. In all treatments, plant damage caused by sucking pest Piezodorus sp and Riptortus linearis were relatively low of 1.53 % to 1.94 %; it indicated an insignificant effect to decline the production. Crop damages by virus showed a significant effect. The lowest virus attacks found on compost of 5 tons per ha with 43 plants infected per treatment, the highest virus attack showed on combination of 5 tons compost per ha + inorganic fertilizer + mulch, in which there were 274 infected plants per treatment. Apparently virus attacks gave impact on soybean production. The highest production were documented on treatment of 5 tons compost per ha with production of 0.55 tons per ha, while the lowest production was found on combination of 5 tons compost per ha + inorganic fertilizer + mulch, in which the production was 0.22 tons per ha. Keywords:  fertilizer, mulch, insect pest, production


Plant Disease ◽  
2019 ◽  
Vol 103 (5) ◽  
pp. 938-943 ◽  
Author(s):  
A. S. Grode ◽  
E. Brisco-McCann ◽  
P. Wiriyajitsonboom ◽  
M. K. Hausbeck ◽  
Z. Szendrei

Onion thrips (Thrips tabaci) is a major insect pest of onion and it has been identified as a likely vector of Pantoea agglomerans (bacterial stalk and leaf necrosis), a relatively new pathogen to Michigan’s onion industry. Our objective was to develop an integrated insect and disease management program by examining the efficacy of bactericides and insecticides alone and in combination to limit bacterial stalk and leaf necrosis caused by P. agglomerans. We also examined the association of onion thrips and disease incidence in the field, because thrips are known to transmit this pathogen. In the pesticide trial, insecticides reduced both thrips abundance and bacterial stalk and leaf necrosis incidence whereas bactericides alone did not reduce disease severity. Positive correlations among thrips population density, numbers of thrips positive for P. agglomerans, and bacterial stalk and leaf necrosis incidence in onion fields were determined. This study suggests that onion thrips feeding can facilitate the development of bacterial stalk and leaf necrosis in Michigan’s commercial onion fields, and results from the pesticide trials indicate that thrips feeding damage is positively correlated with disease incidence. Therefore, in order to reduce bacterial stalk and leaf necrosis incidence in onion, management efforts should include reducing onion thrips populations through the use of insecticides and other cultural practices.


1977 ◽  
Vol 70 (5) ◽  
pp. 659-663 ◽  
Author(s):  
M. Kogan ◽  
S. G. Turnipseed ◽  
M. Shepard ◽  
E. B. De Oliveira ◽  
A. Borgo

2004 ◽  
Vol 17 (4) ◽  
pp. 394-403 ◽  
Author(s):  
Weixing Shan ◽  
Minh Cao ◽  
Dan Leung ◽  
Brett M. Tyler

We have used map-based approaches to clone a locus containing two genes, Avr1b-1 and Avr1b-2, required for avirulence of the oomycete pathogen Phytophthora sojae (Kaufmann & Gerdemann) on soybean plants carrying resistance gene Rps1b. Avr1b-1 was localized to a single 60-kb bacterial artificial chromosome (BAC) clone by fine-structure genetic mapping. Avr1b-1 was localized within the 60-kb region by identification of an mRNA that is expressed in a race-specific and infection-specific manner and that encodes a small secreted protein. When the Avr1b-1 protein was synthesized in the yeast Pichia pastoris and the secreted protein infiltrated into soybean leaves, it triggered a hypersensitive response specifically in host plants carrying the Rps1b resistance gene. This response eventually spread to the entire inoculated plant. In some isolates of P. sojae virulent on Rps1b-containing cultivars, such as P7081 (race 25) and P7076 (race 19), the Avr1b-1 gene had numerous substitution mutations indicative of strong divergent selection. In other isolates, such as P6497 (race 2) and P9073 (race 25), there were no substitutions in Avr1b-1, but Avr1b-1 mRNA did not accumulate. Genetic complementation experiments with P6497 revealed the presence of a second gene, Avr1b-2, required for the accumulation of Avr1b-1 mRNA. Avr1b-2 was genetically mapped to the same BAC contig as Avr1b-1, using a cross between P7064 (race 7) and P6497. The Avr1k gene, required for avirulence on soybean cultivars containing Rps1k, was mapped to the same interval as Avr1b-1.


2018 ◽  
Vol 46 (2) ◽  
pp. 356-364
Author(s):  
Ufkun SARISOY ◽  
Burcu SECKIN DINLER ◽  
Eda TASCI

Non-expressor of Pathogen Related 1 (NPR1) is a regulatory gene of the salicylic acid (SA) signaling pathway, the detailed mechanism of which is still not well understood. This study investigated the effects of NPR1-dependent SA level change on increasing salt tolerance of soybean leaves with acclimation. Salt-sensitive (‘SA88’) and salt-tolerant (‘Erensoy’) soybean (Glycine max L.) plants were treated with increasing NaCl concentrations (25, 50, 75, and 100 mM; acclimation) and with 100 mM NaCl directly (non-acclimation) in two groups. The results showed that acclimation treatment alleviated salt-induced damage in the sensitive cultivar with increasing superoxide anion radical scavenging activity, and decreasing hydrogen peroxide (H2O2) and malondialdehyde (MDA) content. However, the APX, CAT, and GST enzyme activities were increased by acclimation treatment, with the highest increase observed in GST enzymes. Interestingly, the Gmnpr1 gene expression was upregulated in all treatments but was more pronounced in non-acclimation. Furthermore, the highest increase in endogenous SA level was under acclimation treatment in ‘SA88’. In conclusion, the results firstly showed that an acclimation process is useful for increasing salt tolerance in sensitive soybean plants with only ROS-inducted NPR1-independent SA accumulation but not through the NPR1-dependent SA signaling pathway.


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