PRELIMINARY ACTIONS IN MAKING PHEROMONE CAPTURERS OF MELON FLY

The article presents information about fields of agricultural production of the Republic of Karakalpakstan, the increase of the requirement for food as a result of increasing the number of population. It was shown that it is important to synthesize pistil of the pest, which is the basic material, in making pheromone capturers of the most dangerous pest of agricultural crops – melon fly. In this, capturing instrument, collecting orders of worms and pupas with the help of protector small gardens were shown. KEYWORDS: melon fly, pistil pest, worm, pupa, capturer, small protecting gardens, collecting.

BIOECOLOGICAL DEVELOPING PECULIARITIES OF MELON FLY AND CONTROLLING ACTIONS

The article describes the development of biological and ecological features and harmfulness of melon fly on crops of melons in conditions of Karakalpakstan. It is studied the efficiency of the deep autumn plowing of soil against overwintering pests, special traps to kill the larvae and pupae, chemical treatments against the imaginal phase melon fly on crops of melon. The impact on the conservation of wild melon pest overwintered individuals. Recommended optimal protective measures in extreme conditions of Karakalpakstan. KEYWORDS. Melon fly, melon, pest, biological, chemical treatment efficacy.

Flight muscle and flight activity of melon fly, Bactrocera cucurbitae (Diptera: Tephritidae)

The flight activity and flight muscle of the melon fly, Bactrocera cucurbitae (Coquillett) (Diptera: Tephritidae) were observed. The Tethered technique was used to observe the flight activity in this study. The flight activity, and wing and flight muscles were compared between male and female melon flies. The results indicate that the female was relatively better and strong flier than the male. The mean duration of the flight activity of the females was 13.90 min/hour and of the males was 7.12 min./hour. The mean length, width, volume of wings of the males were 6.07 mm, 2.67 mm and 10.99 mm³, respectively. On the other hand, the mean length, width and volume of the wings of females were 7.07 mm, 2.87 mm and 15.60 mm³, respectively. In case of wing muscles, the mean volume of dorsal longitudinal muscle (DLM) in male and female was found 5.20 mm³ and 5.67 mm³, respectively. The mean length of flight wing muscle of male and female was 2.22 and 2.23 mm, respectively and the mean breadth of male and female was 1.65 and 1.77 mm, respectively. Dhaka Univ. J. Biol. Sci. 30(2): 179-185, 2021 (July)

RNAi-Mediated Knockdown of Imaginal Disc Growth Factors (IDGFs) Genes Causes Developmental Malformation and Mortality in Melon Fly, Zeugodacus cucurbitae

This study reports the first successful use of oral feeding dsRNA technique for functional characterization of imaginal disc growth factors (IDGFs) genes (IDGF1, IDGF3_1, IDGF4_0, IDGF4_1, and IDGF6) in melon fly Zeugodacus cucurbitae. Phylogenetic and domain analysis indicates that these genes had high similarity with other Tephritidae fruit flies homolog and contain only one conserved domain among these five genes, which is glyco-18 domain (glyco-hydro-18 domain). Gene expression analysis at different developmental stages revealed that these genes were expressed at larval, pupal, and adult stages. To understand their role in different developmental stages, larvae were fed dsRNA-corresponding to each of the five IDGFs, in an artificial diet. RNAi-mediated knockdown of IDGF1 shows no phenotypic effects but caused mortality (10.4%), while IDGF4_0 caused malformed pharate at the adult stage where insects failed to shed their old cuticle and remained attached with their body, highest mortality (49.2%) was recorded compared to dsRNA-green fluorescent protein (GFP) or DEPC. Silencing of IDGF3_1 and IDGF4_1 cause lethal phenotype in larvae, (17.2%) and (40%) mortality was indexed in Z. cucurbitae. IDGF6 was mainly expressed in pupae and adult stages, and its silencing caused a malformation in adult wings. The developmental defects such as malformation in wings, larval–larval lethality, pupal–adult malformation, and small body size show that IDGFs are key developmental genes in the melon fly. Our results provide a baseline for the melon fly management and understanding of IDGFs specific functions in Z. cucurbitae.

Dacus ciliatus (lesser pumpkin fly).

D. ciliatus is a major pest of a wide range of Cucurbitaceae in Africa, Asia and the Middle East. Adult flight and fruit transport are major means of dispersal. It may cause indirect economic impact on exports and could become a serious pest if introduced in the USA. It is an EPPO A1 quarantine pest within the category 'non-European Trypetidae' and is also of quarantine significance to CPPC (Caribbean Plant Protection Commission). Demographics, the main component of competition for fly species, have only been studied for this species by Vayssières et al. (2008). Compared to Bactrocera cucurbitae, it has longer egg incubation and immature stages, both disadvantages when competing for the same habitat. Preference for certain hosts allows D. ciliatus to enhance its biotic potential and maintain low population levels when competing with the melon fly, especially at low altitudes. D. ciliatus could colonize low temperature areas, as has been the case in Mediterranean areas. D. ciliatus seems less wiling to exploit new hosts compared to B. cucurbitae.