scholarly journals Compatibility of indigenous isolates HR1, HR2 of entomopathogenic nematodes, with low-toxicity insecticides for control of fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) and tomato leafminer, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae)

Author(s):  
Indra Kumar Kasi ◽  
Mohinder Singh ◽  
Kanchhi Maya Waiba

Abstract Invasive species are a major danger to agronomic and natural ecosystems, and due to environmental concerns about pesticide use, EPNs have the potential to replace larvicidal action in pest management. The goal was to see how well local isolates of Steinernema feltiae (HR1) and Heterorhabditis bacteriophora (HR2) controlled invasive species when combined with low-toxicity pesticides. HR1 + Spinosad, chlorantraniliprole produced over 90% mortality in larvae at 96 hours, while HR2 + Spinosad, chlorantraniliprole caused over 95% mortality at 96 hours. After treatment, the high dose was regarded the least hazardous technique for controlling fall armyworm. At the high dose, HR1 + Spinosad, chlorantraniliprole produced larvae death of over 100 percent at 96 hours, and HR2 + Spinosad, chlorantraniliprole caused mortality of over 97.50 percent at 96 hours, and should be considered as a least hazardous strategy for T. absoluta management. Controlling larvae mortality of above 100% at 96 hours in combination with low-toxicity insecticide dosages should be included as a least harmful technique to control T. absoluta. The results showed that these HR2 strains have high pathogenicity against T. absoluta and S. frugiperda and have potential for control in integrated approaches, causing 100 percent and 90.00 percent mortality of T. absoluta and S. frugiperda at 96 hours at the high dose as a least toxic strategy to control.

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Wandee Wattanachaiyingcharoen ◽  
Ongpo Lepcha ◽  
Apichat Vitta ◽  
Det Wattanachaiyingcharoen

Abstract Background Under laboratory and greenhouse conditions, the virulence of 2 isolates of Thai indigenous entomopathogenic nematodes (EPNs) in controlling the fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith) (Lepidoptera; Noctuidae), was demonstrated. Six EPNs dosages were tested against 2 larval instars of FAW under the laboratory conditions, while 2 different concentrations were tested under the greenhouse conditions. Results The results of a laboratory experiment revealed that 2 Thai indigenous EPNs isolates (Heterorhabditis indica isolate AUT 13.2 and Steinernema siamkayai isolate APL 12.3) were efficient against the FAW, 2nd and 5th larval instars. Six different nematode concentrations (50,100, 150, 200, 250 and 300 infectious juveniles (IJs) ml−1) were evaluated, and all were proven to be effective, with the mortality rate associated with concentration. Inoculated larvae in the 2nd instar was more vulnerable than that in the 5th instar. H. indica isolate AUT 13.2 was more destructive than S. siamkayai isolate APL 12.3. The greatest mortality rate of 2nd instar larvae was 83% when H. indica AUT 13.2 was applied at the concentration of 250 IJs ml−1, and 68% when the nematode S. siamkayai APL 12.3 was used at the concentration of 300 IJs ml−1. At 250 IJsml−1, the highest mortality rate of the 5th instar larvae was 45% for H. indica AUT 13.2 and 33% for S. siamkayai APL 12.3, respectively. To customize the concentration and volume of nematodes suspension evaluated in the greenhouse settings, the most sensitive stage of FAW and the optimum concentration that caused the highest mortality were used. The concentrations of both indigenous nematodes’ isolates were 20,000 and 50,000 IJsml−1 per pot, respectively, and the results showed that the mortality rates were lower than that in the laboratory. FAW mortality rate was the highest (58%) in case of the nematode H. indica isolate AUT 13.2, against (45%) in case of S. siamkayai isolate APL 12.3, at the 50,000 IJs ml−1 concentrations. Conclusions The study revealed the 2 Thai indigenous EPNs isolates (H. indica isolate AUT 13.2 and S. siamkayai isolate APL 12.3) were capable of controlling the FAW in both laboratory and greenhouse environments. The 2 Thai EPNs showed the potential to be considered as a biological control agent.


Author(s):  
Maribel Rivero-Borja ◽  
J C Rodríguez-Maciel ◽  
J A Urzúa Gutiérrez ◽  
G Silva-Aguayo ◽  
Desmi I Chandrasena ◽  
...  

Abstract The fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), is currently the most important maize pest in Mexico. Its control is mainly based on the use of conventional insecticides. Additionally, Bt-maize expressing Cry1F protein represents an alternative to control this pest. We estimated the baseline susceptibility in Mexican populations of S. frugiperda to Cry1F protein. Twenty-eight geographical populations were field collected from Baja California Sur, Chihuahua, Coahuila, Durango, Sinaloa, Sonora, and Tamaulipas states. The F1 neonate larvae of each population were subjected to diet-overlay bioassay. After 7 d of Cry1F exposure, the percent mortality and the percent growth inhibition with respect to the untreated control were recorded (S-LAB). The LC50 ranged from 14.4 (6.3−24.0) (Cajeme 1, Sonora) to 161.8 ng/cm2 (92.0–320) (Ahumada 2, Chihuahua), while the LC95 was between 207.1 (145–363) (Obregón, Sonora) and 1,217 ng/cm2 (510.8–7,390.0) (Río Bravo 2, Tamaulipas). The sensitivity ratios at 50% mortality, (LC50 field/LC50 S-Lab) and 95% mortality were ≤6.45 and ≤5.05-fold, respectively. The 50% growth inhibition (GI50) ranged from 2.8 (0.008–9.3) (Obregón, Sonora) to 42.4 ng/cm2 (3.6–147.0) (Cajeme 1, Sonora). The GI95 was between 75.4 (San Luis Río Colorado, Sonora) to 1,198 ng/cm2 (Cajeme 1, Sonora). The relative inhibition at 50% of the growth, (RI50 = GI50 field /GI50 S-LAB) was ≤3.5 and at 95% (RI95) was ≤1.91-fold. These results indicated susceptibility to Cry1F protein in the evaluated populations of S. frugiperda.


2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Hrang Chal Lalramnghaki ◽  
Lalramliana ◽  
Hmar Tlawmte Lalremsanga ◽  
Vanlalhlimpuia ◽  
Mary Lalramchuani ◽  
...  

Abstract Background Outbreak of the fall armyworm Spodoptera frugiperda (J.E. Smith, 1797) (Lepidoptera: Noctuidae) occurred in Mizoram, North-Eastern India. The infestation spread in the entire state covering a total area of around 2840 hectares of maize cultivated land. Entomopathogenic nematodes (EPNs) represent potential candidates for the biological control of S. frugiperda. In the study, the susceptibility of the pest against 4 locally isolated EPN species Heterorhabditis indica, H. baujardi, Steinernema sangi and S. surkhetense was evaluated. Results The results indicated that all the isolated EPN species showed a high rate of larvicidal and pupicidal activities against the pest. Mortality between 43.75–100.00 and 25.00–100.00% of 3rd and 5th larval instars, respectively (at concentrations 10–800 IJs/larva), and 37.50–68.75% mortality of pupae (at concentrations 200–1600 IJs /pupa) were found after exposure to the EPN species. The mortality rate of the pest showed significant variations with life stages of the host insect, nematode concentrations and incubation time. Based on the median lethal concentration (LC50), H. indica was the most pathogenic species, followed by S. sangi, H. baujardi and S. surkhetense. The LC50 values of H. indica at 72 h post-incubation were 20.26 and 62.07 IJs/larva for the 3rd and 5th larval instars, respectively, and 913.34 IJs/pupa. The penetration assay showed that H. indica had the highest penetration rate into the hosts, 27.24, 21.30 and 20.00% in the 3rd, 5th larval instars and pupae, respectively. Furthermore, all the EPN isolates were capable of successful multiplication inside the cadaver of S. frugiperda that showed significant differences with the EPN isolates and life stages of the pest. Among the isolates, H. indica showed the highest multiplication rates, 17,692.25 ± 2103.59, 8345.63 ± 785.34 and 79,146.38 ± 5943.73 IJs per 3rd instar larva, 5th instar larva and pupa, respectively. Conclusions The study revealed that the 4 species of EPNs showed a high potency against S. frugiperda, thereby having the potential to be developed as a biological control agent against the pest. Moreover, the isolated EPN species could potentially serve as alternatives for chemical insecticides and could further be incorporated into the Integrated Pest Management (IPM).


Agronomy ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1074
Author(s):  
Bonoukpoè Mawuko Sokame ◽  
Boaz Musyoka ◽  
Julius Obonyo ◽  
François Rebaudo ◽  
Elfatih M. Abdel-Rahman ◽  
...  

The interactions among insect communities influence the composition of pest complexes that attack crops and, in parallel, their natural enemies, which regulate their abundance. The lepidopteran stemborers have been the major maize pests in Kenya. Their population has been regulated by natural enemies, mostly parasitoids, some of which have been used for biological control. It is not known how a new exotic invasive species, such as the fall armyworm (FAW), Spodoptera frugiperda (Lepidoptera, Noctuidae), may affect the abundance and parasitism of the resident stemborers. For this reason, pest and parasitism surveys have been conducted, before and after the FAW invaded Kenya, in maize fields in 40 localities across 6 agroecological zones (AEZs) during the maize-growing season, as well as at 3 different plant growth stages (pre-tasseling, reproductive, and senescence stages) in 2 elevations at mid-altitude, where all maize stemborer species used to occur together. Results indicated that the introduction of the FAW significantly correlated with the reduction of the abundance of the resident communities of maize stemborers and parasitoids in maize fields; moreover, the decrease of stemborer density after the arrival of FAW occurred mostly at both reproductive and senescent maize stages. It also suggests a possible displacement of stemborers by FAW elsewhere; for example, to other cereals. However, since this study was conducted only three years after the introduction of the FAW, further studies will need to be conducted to confirm such displacements.


2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Sharanabasappa S. Deshmukh ◽  
S. Kiran ◽  
Atanu Naskar ◽  
Palam Pradeep ◽  
C. M. Kalleshwaraswamy ◽  
...  

AbstractThe fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), has become a major threat in maize cultivation since its invasion to India in 2018. The humpbacked fly, Megaselia scalaris (Loew) (Diptera: Phoridae), was recorded as a laboratory parasitoid of FAW, for the first time in India. Initially, 30–40 maggots of M. (M) scalaris emerged out from the dead pre-pupa and pupa of laboratory-reared FAW. The fly laid up to 15 eggs on the outer surface of 6th instar larva or pre-pupa of the FAW. The incubation period was 1–2 days. The fly had 3 larval instars which lasted 3–4 days and a pupal period of 10–11 days. The adults survived for 6–7 days.


2013 ◽  
Vol 63 (2) ◽  
pp. 185-197 ◽  
Author(s):  
Franklin M. Cunha ◽  
Valéria Wanderley-Teixeira ◽  
Jorge B. Torres ◽  
Álvaro A.C. Teixeira ◽  
Thiago J.S. Alves ◽  
...  

Despite the efficiency of transgenic plants expressing Bacillus thuringiensis (Bt) toxins as insecticides against several lepidopterans, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) is one species that presents low susceptibility to most Bt crops. This study investigated the effects of the Cry1Ac toxin expressed by Bt cotton in the midgut of S. frugiperda and its effects on the humoral and cellular immune responses. Three hypotheses were proposed and tested with contributing factors for the natural tolerance of S. frugiperda: (i) midgut regenerative cells are activated by the Cry1Ac toxin, and thus renew the epithelial cells damaged by the protein, (ii) Cry1Ac increased production of nitric oxide or phenoloxidase in the hemolymph, and (iii) there are qualitative and quantitative variations in the hemocyte levels of S. frugiperda. Caterpillars were reared using Bt cotton (Acala 90B) and non-Bt isolines (Acala 90), from the first to the fourth instar. The Bt cotton promoted elongation of the epithelial cells in the midgut of S. frugiperda caterpillars. Hence, evidence only supported the hypothesised increase of phenoloxidase (ii) and qualitative and quantitative differences in hemocyte levels (iii) in insects that were fed with Bt and non-Bt cotton. These parameters seem to explain the low susceptibility of S. frugiperda to Cry1Ac toxin and they are a viable set of responses for the evaluation of other xenobiotic factors.


2019 ◽  
Vol 11 (4) ◽  
pp. 126
Author(s):  
Lauren M. Barcelos ◽  
Fabrício O. Fernandes ◽  
Caroline Lopes ◽  
Beatriz M. Emygdio ◽  
Ricardo Valgas ◽  
...  

Saccharine sorghum has been analyzed as a supplementary prime matter for ethanol production, especially during the sugarcane off-season period. However, it has proven to be highly susceptible to insect attacks during the cultivation cycle. The fall armyworm should be emphasized due to its voracity and high damage capacity enhanced by feeding-caused decrease in photosynthetic area. Current analysis studies the biology and determines the nutritional indexes of Spodoptera frugiperda in saccharine sorghum. Cultivars of saccharine sorghum BRS 506, BRS 509 and BRS 511were evaluated. Duration and survival of the egg, caterpillar, pre-pupal and pupal phases were determined, coupled to weight of pupae and caterpillar, life span, fecundity and pre-egg laying period. Although S. frugiperda completed its life cycle on cultivars BRS 506 and BRS 511, egg-laying and egg feasibility rates were low, whereas insects did not lay eggs on cultivar BRS 509. There was no significant difference in feeding intake by S. frugiperda among these three sorghum cultivars. Results suggest that saccharine sorghum is not a suitable host for S. frugiperda. Biological data reveal that the three saccharine sorghum cultivars are recommended for the grain production system since the number of specimens of the next generation is low or null.


2008 ◽  
pp. 1409-1412
Author(s):  
E. S. Krafsur ◽  
R. D. Moon ◽  
R. Albajes ◽  
O. Alomar ◽  
Elisabetta Chiappini ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document