Zeugodacus Cucurbitae Coquillett Research Articles

Phytosanitary cold treatment of cherry tomatoes infested with Bactrocera dorsalis, Zeugodacus cucurbitae, and Zeugodacus tau (Diptera: Tephritidae).

Fruit flies attack numerous crops, including cherry tomatoes (Solanum lycopersicum var. cerasiforme). The potential presence of the immature stages of fruit fly species inside tomatoes during export hinders their international market access. Therefore, phytosanitary treatment must be performed before export to prevent fruit fly species from entering countries where they are not naturally found. We developed a phytosanitary cold disinfestation treatment protocol to eliminate oriental fruit fly (Bactrocera dorsalis Hendel), melon fly (Zeugodacus cucurbitae Coquillett), and pumpkin fruit fly (Zeugodacus tau Walker) concealed inside cherry tomatoes without causing critical damage to the fruit. We determined that the third instar of Z. cucurbitae exhibited the highest cold tolerance among the various development stages of the three fruit fly species. Thus, we performed a small-scale disinfestation test on Z. cucurbitae in two cultivars of tomato. We achieved complete disinfestation after 15 days of cold treatment at 1°C-1.5°C. The confirmatory test revealed the elimination of more than 80,000 treated third instar of Z. cucurbitae in each tomato variety. The developed phytosanitary cold treatment allows the tomatoes to retain their commercial value. This study provides a standard phytosanitary cold treatment protocol for cherry tomatoes, ensuring the disinfestation of fruit flies before their export to international markets.

Screening of indigenous Bacillus thuringiensis for dipteran active cry gene profiles and potential toxicity against melon fruit fly, Zeugodacus cucurbitae (Coquillett)

BackgroundMelon fruit fly, Zeugodacus cucurbitae Coquillett (Diptera: Tephritidae), is a devastating polyphagous pest attacking large number of fruits and vegetables causing huge economic yield losses across the world. Management of this notorious pest is very challenging as the larvae feed inside the fruit. Hence, the present research study aimed to screen the indigenous Bacillus thuringiensis Berliner (Bacillales: Bacillaceae) strains causing toxicity to larvae and to identify the insecticidal toxicity-related genes present in respective strains. In the present study, 50 indigenous B. thuringiensis (Bt) strains along with one reference strain were screened against second-instar larvae Z. cucurbitae. All the strains were analyzed for presence of 21 dipteran active cry genes.ResultsMortality in Z. cucurbitae larvae due to Bt strains ranged from 16 to 92%. PCR results revealed that each strain tested positive for a minimum of three cry genes to maximum of nine cry genes. Among the cry genes, cry1A, cry2A, cry1C, cry19, cry11 and cry70 were detected in high frequency of 100, 88, 84, 74, 58 and 54%, respectively. Bioassay studies revealed that ten out of fifty strains displayed more than 50% mortality. Hence, these ten strains, along with the reference strain, were further tested for mortality for the calculation of the median lethal concentration (LC50). The LC50 values ranged between 38.48 and 105.18 μg/ml. The lowest LC50 found for the strain NBAIR Bt107 was 38.48 μg/ml and was on par with the reference strain (Bti 4Q1) (31.3 μg/ml).ConclusionIndigenous Bt strains displayed a toxicity against the larvae of Z. cucurbitae. The probable dipteran active cry genes responsible for toxicity were interpreted. Thus, the Cry toxins from Bt can play a very important role in the management of Z. cucurbitae.

Overexpression of miR-927-5p suppresses stalky expression and negatively reduces the spermatid production in Zeugodacus cucurbitae.

The melon fly, Zeugodacus cucurbitae Coquillett, is one of the major pests attacking Cucurbitaceae crops. Identifying critical genes or proteins regulating fertility is essential for sustainable pest control and a research hotspot in insect physiology. MicroRNAs (miRNAs) are short RNAs that do not directly participate in protein translation, but instead function in post-transcriptional regulation of gene expression involved in male fertility. We found that miR-927-5p is highly expressed in the testes and investigated its function in spermatogenesis in Z. cucurbitae. Fluorescence in situ hybridization (FISH) showed miR-927-5p in the transformation and maturation region of the testis, and overexpression of miR-927-5p reduced the number of sperms by 53%. In continuation, we predicted 12 target genes of miR-927-5p using bioinformatics combined with transcriptome sequencing data, and found that miR-927-5p targets the new gene Stalky in insects, which was validated by quantitative real-timePCR, RNA pull-down and dual luciferase reporter assays. FISH also confirmed the co-localization of miR-927-5p and the transcript Stalky_1 in the testis. Moreover, silencing of Stalky_1 by RNA interference reduced the number of sperms by 32% and reduced sperm viability by 39% in physiologically mature male adults. Meanwhile, the silencing of Stalky_1 also resulted in low hatchability. Our work not only presents a new, so far unreported mechanism regulating spermatogenesis by miR-927-5p targeting a new unknown target, Stalky, which is providing new knowledge on the regulatory network of insect spermatogenesis, but also lays a foundation for the development of SIT against important tephritid fly pests. © 2024 Society of Chemical Industry.

Suppressing the expression of glutathione S-transferase gene GSTd10 increases the sensitivity of Zeugodacus cucurbitae against β-cypermethrin.

Zeugodacus cucurbitae Coquillett (Diptera: Tephritidae) is an agriculturally and economically important pest worldwide that has developed resistance to β-cypermethrin. Glutathione S-transferases (GSTs) have been reported to be involved in the detoxification of insecticides in insects. We have found that both ZcGSTd6 and ZcGSTd10 were up-regulated by β-cypermethrin induction in our previous study, so we aimed to explore their potential relationship with β-cypermethrin tolerance in this study. The heterologous expression of ZcGSTd6 and ZcGSTd10 in Escherichia coli showed significantly high activities against 1-chloro-2,4-dinitrobenzene (CDNB). The kinetic parameters of ZcGSTd6 and ZcGSTd10 were determined by Lineweaver-Burk. The Vmax and Km of ZcGSTd6 were 0.50 μmol/min·mg and 0.3 mM, respectively. The Vmax and Km of ZcGSTd10 were 1.82 μmol/min·mg and 0.53 mM. The 3D modelling and molecular docking results revealed that β-cypermethrin exhibited a stronger bounding to the active site SER-9 of ZcGSTd10. The sensitivity to β-cypermethrin was significantly increased by 18.73% and 27.21%, respectively, after the knockdown of ZcGSTd6 and ZcGSTd10 by using RNA interference. In addition, the inhibition of CDNB at 50% (IC50) and the inhibition constants (Ki) of β-cypermethrin against ZcGSTd10 were determined as 0.41 and 0.33 mM, respectively. The Ki and IC50 of β-cypermethrin against ZcSGTd6 were not analysed. These results suggested that ZcGSTd10 could be an essential regulator involved in the tolerance of Z. cucurbitae to β-cypermethrin.

Geranium Aralia, Polyscias guilfoylei (W. Bull) L.H. Bailey), Leaf Extract Toxicity against Melon Fly, Zeugodacus cucurbitae Coquillett

Zeugodacus cucurbitae Coquillett is one of the most detrimental pests that mostly attack family Cucurbitaceae. Control over this pest often uses insecticides, and one of the plants with the potentiality to be used as source of insecticide is Polyscias guilfoylei. This research aimed to study the influence of P. guilfoylei leaf extract application upon Z. cucurbitae mortality and to determine the LC50 value. The research was conducted at Pest Invertebrate Plant Pest Science Laboratory, Department of Plant Protection, Faculty of Agriculture, Universitas Gadjah Mada. The toxicity test was done using contact, oral and residue methods upon ethanol and n-hexane extracts with 0; 1.25; 2.50; 5.00; 10.00; and 20.00% concentrations. The research used randomized group design with six replications. The parameters observed were the number of dead melon fly at 72 hours after the treatment and LC50 value of each extract. The data were analyzed using Probit analysis via 1.02 version of Lenora software Polo Plus. The result shows that ethanol and n-hexane extracts of P. guilfoylei leaf using oral and residue methods affected Z. cucurbitae mortality. However, in contact method, ethanol and n-hexane extracts of P. guilfoylei leaf did not affect Z. cucurbitae mortality. LC50 values of ethanol extract using oral and residual methods were 6.168% and 3.658%, respectively. LC50 values of n-hexane extract using oral and residual method reached 5.311% and 6.607%, respectively. This research shows that ethanol and n-hexane extracts of P. guilfoylei leaf contain secondary metabolites that are toxic for melon fly Z. cucurbitae.

Expression and function of opsin genes associated with phototaxis in Zeugodacus cucurbitae Coquillett (Diptera: Tephritidae).

Zeugodacus cucuribitae is a major agricultural pest that causes significant damage to varieties of plants. Vision plays a critical role in phototactic behavior of herbivorous insects. However, the effect of opsin on the phototactic behavior in Z.cucuribitae remain unknown. The aim of the research is to explore the key opsin genes that associate with phototaxis behavior of Z. cucurbitae. We identified five opsin genes and analyzed their expression patterns. The relative expression levels of ZcRh1, ZcRh4 and ZcRh6 were highest in 4-day-old larvae, ZcRh2 and ZcRh3 were highest in 3rd-instar larvae and 5-day-old pupae, respectively. Furthermore, five opsin genes had the highest expression levels in compound eyes, followed by the antennae and head, whereas the lower occurred in other tissues. The expression of the long-wavelength-sensitive (LW) opsins first decreased and then increased under green light exposure. In contrast, the expression of ultraviolet-sensitive (UV) opsins first increased and then decreased with the duration of UV exposure. Silencing of LW opsin (dsZcRh1, dsZcRh2, and dsZcRh6) and UV opsin (dsZcRh3 and dsZcRh4) reduced the phototactic efficiency of Z. cucurbitae to green light by 52.27%, 60.72%, and 67.89%, and to UV light by 68.59% and 61.73%, respectively. The study found that RNAi inhibited the expression of opsin, thereby inhibiting the phototaxis of Z. cucurbitae. This result provides theoretical support for the physical control of Z. cucurbitae and lays the foundation for further exploration of the mechanism of insect phototaxis. This article is protected by copyright. All rights reserved.

Monitoring of Melon Fruit Fly, Zeugodacus cucurbitae Coquillett Population using Para-pheromone Traps in Bitter Gourd (Momordica charantia L.)

Investigations were carried out on monitoring of melon fruit fly, Zeugodacus cucurbitae Coquillett on bitter gourd (Momordica charantia L.) using para-pheromone traps during Kharif, 2018-19 at CCS HAU, Hisar. The incidence of Z. cucurbitae started gradually and increased from 31st to 42nd Standard Meteorological Week (SMW) corresponding to the 1st week of September to 3rd week of October. Higher number of fruit flies (on average 9.5 to 40.5 flies/trap) were recorded in the month of September to first fortnight of October with a peak of 40.5 flies/trap during 37th SMW. Correlation analysis with various weather parameters indicated that maximum temperature (r = 0.611*), morning relative humidity (0.590*) and rainfall (0.747**) had significant positive correlation with trap catch population of melon fruit fly. The present findings also revealed that the influence of all-weather parameters was high and significant on trap catches population of the adult male melon fruit fly (R2=0.76).

Active compounds and biological activities of geranium aralia (Polyscias guilfoylei (W. Bull) L.H. Bailey) leaf extract against larval stage of melon fly (Zeugodacus cucurbitae Coquillett)

Active compounds and biological activities of geranium aralia (Polyscias guilfoylei (W. Bull) L.H. Bailey) leaf extract against larval stage of melon fly (Zeugodacus cucurbitae Coquillett)

Evaluation of Control Methods for Fruit Flies (Diptera: Tephritidae) on Watermelon (Citrullus lanatus (Thumb) Matsum & Nakai) in The Gambia

Commercial production of watermelon (Citrullus lanatus (Thunb.) Matsum & Nakai) is increasing in The Gambia, but tephritid fruit flies present a huge challenge to its production. To avoid severe losses, watermelon growers often resort to indiscriminate use of pesticides to manage the pest. Field studies were conducted at two sites (Faraba and Site 3) in the West Coast Region of The Gambia to evaluate two environmentally friendly options (Success Appat (GF-120) and Cocoa Butter Cream) for management of fruit flies on the crop. Dimethoate insecticide, the farmers’ preferred choice, was used as a chemical check and untreated control plots were also maintained. The field plots were arranged in Randomized Complete Block Design and the treatments were replicated three times. The results of the study showed that, even though three species of fruit flies, Bactrocera dorsalis (Hendel), Dacus vertebratus Bezzi and Zeugodacus cucurbitae Coquillett were collected at both study sites, only D. vertebratus infested watermelon fruits. Both Success Appat (GF-120) and Cocoa Butter Cream reduced watermelon fruit infestation and, generally, provided comparable protection as the check (Dimethoate) to watermelon fruits against fruit flies and therefore would be suitable replacements.

Flight Burst Duration as an Indicator of Flight Ability and Physical Fitness in Two Species of Tephritid Fruit Flies.

We introduce a method to quantify flight ability and physical fitness of individual fruit flies which we term 'Flight Burst Duration' (FBD). This consisted of tethering individual insects by the dorsal thorax using a vacuum and measuring the length of time the insect beats its wings while suspended off a surface. Consecutive measurements with Bactrocera dorsalis Hendel (Dipera: Tephritidae) and Zeugodacus cucurbitae Coquillett (Diptera: Tephritidae) in the same day and across days indicated that a single measurement was sufficient, and that FBD was consistent and repeatable. Insects under stress from starvation displayed shorter FBD over time, and we suggest that the measure also relates to the physical condition or survival fitness of the individual. Though somewhat laborious and time-consuming, we propose that FBD can be useful for research studies requiring individual-level phenome data and for obtaining estimates quality and dispersive movement for insects.