Seasonal Abundance of Melon Fruit Fly, Bactrocera cucurbitae (Coquillett) Infesting Cucumber in Relation to Abiotic Factors

The present investigation on seasonal abundance of melon fruit fly in relation to weather parameters was conducted in cucumber at the farmers field, Kharsad, Navsari, Gujarat using Nauroji Stonehouse fruit fly trap containing cue-lure baited wooden block during summer 2022. Studies on seasonal abundance revealed that in cucumber the activity of adults of B. cucurbitae commenced from 13th Standard Meteorological Week (SMW) i.e., 4th week of March and continued till 19th SMW (1st week of May) which ranged from 38.00 to 59.75 with an average of 45.11 male fruit flies per four traps while, the peak adult population was observed during 17th SMW i.e., 4th week of April (59.75 mean male fruit flies/4 traps). Moreover, adult population of melon fruit fly showed positive and significant correlation with maximum temperature and negative and significant correlation with morning relative humidity.

Impact of Weather Parameters on Population Dynamics of Fruit Flies (Bactrocera sp.) on Phalsa (Grewia asiatica Linn.)

Field experiments were meticulously conducted for two consecutive years (2018 and 2019) at a phalsa orchard situated in the Regional Horticulture Research Station (RHRS), Raya, District-Samba. The primary aim of these experiments was to comprehensively examine the population dynamics of fruit flies and their susceptibility to variations in weather parameters. To this end, green valley fruit fly traps were strategically deployed throughout the orchard to monitor fruit fly populations. The outcomes of the study revealed that fruit fly activity commenced during the 15th standard week and reached its zenith during the 24th standard week in both years. Correlation analysis underscored a notably strong and positive correlation with maximum (0.575**) and minimum (0.696**) temperatures. Furthermore, a significant negative correlation (–0.422*) was observed between morning relative humidity and fruit fly catches. However, the study did not find any statistically significant correlation between evening relative humidity, rainfall, and fruit fly captures. The weather conditions accounted for an impressive 59.70% of the observed variations in adult fruit fly trap catches of B. dorsalis and B. zonata on phalsa which highlighted the intricate interplay between environmental factors and the population dynamics of these fruit fly species in the phalsa crop ecosystem.

Purification of Colocasia esculenta lectin and determination of its anti-insect potential towards Bactrocera cucurbitae.

The present study reports the purification of a lectin from Colocasia esculenta (L.) Schott corms and evaluation of its anti-insect potential towards Bactrocera cucurbitae (Coquilett). The lectin was found to be specific towards N-acetyl-D-lactosamine (LacNac), a disaccharide and asialofetuin, a desialylated serum glycoprotein in hemagglutination inhibition assay. Asialofetuin was used as a ligand to purify Colocasia esculenta agglutinin (CEA) by affinity chromatography. The purity of CEA was ascertained by the presence of a single band in reducing SDS-PAGE at pH 8.3. The affinity purified CEA was employed in artificial diet bioassay of second instar larvae (64-72 hr old) of the B. cucurbitae at concentrations ranging between 10-160 µg ml-1. The lectin significantly (p<0.01) decreased the percent pupation and emergence with respect to control. Effect on various enzymes was studied by employing LC50 (51.6 µg ml-1) CEA in the artificial diet bioassay of second instar larvae. All the enzymes tested namely esterases, phosphatases (acid and alkaline), superoxide dismutases, catalase and glutathione-S-transferase showed a significant (p<0.01, p<0.05) increase in their enzyme and specific activities. These results showed that CEA affected normal growth and development and presented stress to the larvae, activating their detoxification and anti-oxidant systems. Thus, the lectin seems to be a useful candidate for the control measures of B. cucurbitae under the integrated pest management (IPM) system.

Effects of Curcuma longa extracts on mortality and fecundity of Bactrocera zonata (Diptera: Tephritidae) / Efeitos dos extratos de Curcuma longa sobre mortalidade e fecundidade de Bactrocera zonata (Diptera: Tephritidae)

The peach fruit fly, Bactrocera zonata, is a significant pest of fruit and vegetable crops in South East Asia and Pacific region. Ccontrol strategies of fruit flies, relying chiefly on insecticides, have serious environmental consequences, disturbing the agro-ecosystem as well as eliminating natural enemies. This study was oriented at exploring the potential of turmeric, Curcuma longa, extracts to control the peach fruit fly. Freshly emerged female adults of Bactrocera zonata were continuously fed for 16 days on diet containing 1000, 500 and 250 ppm of acetone extract of Curcuma longa separately in laboratory cages. The extract caused 85.00, 66.67 and 56.67 percent mortality at 1000, 500 and 250 ppm respectively. The surviving females were mated and allowed to reproduce on clean guava fruits in separate cages. The inhibition in pupal progeny was 67.90, 60.74 and 51.96 percent in the flies fed on 1000, 500 and 250 ppm, the inhibition observed in adult progeny was 84.68, 79.03 and 67.74 percent, respectively.

A mosca do pêssego, Bactrocera zonata, é uma importante praga das frutas e produtos hortícolas no Sudeste Asiático e Pacífico. As estratégias de controle de moscas-das-frutas, que se baseia principalmente no uso de inseticidas, têm consequências ambientais graves, perturbando o agroecossistema, bem como eliminando os inimigos naturais. Este estudo foi orientado a explorar as potencialidades dos extratos de açafrão Curcuma longa para controle de B. zonata. Após a emergência, adultos de fêmeas de B. zonata foram continuamente alimentados, durante 16 dias, com dieta contendo 1000, 500 e 250 ppm de extrato acetônico de C. longa separadamente em gaiolas no laboratório. O extrato causou 85,00, 66,67 e 56,67 por cento de mortalidade em 1000, 500 e 250 ppm, respectivamente. As fêmeas foram acasaladas e postas para ovipositar separadamente em goiabas dentro das gaiolas. A inibição na progênie pupal foi 67,90, 60,74 e 51,96 por cento nos insetos alimentados em 1000, 500 e 250 ppm, a inibição observada na progênie adulta foi 84,68, 79,03 e 67,74 por cento, respectivamente.

Anti-insect potential of lectins from Arisaema species towards Bactrocera cucurbitae.

Bactrocera cucurbitae (Coquillett), also known as melon fruit fly, is one of the major insect pests of cucurbits in several parts of Asia, Africa and Pacific. In the present investigation, effect of lectins from two sources i.e. Arisaema intermedium Blume and Arisaema wallichianum Hook f. (Family-Araceae) has been studied on the development of second instar larvae of melon fruit fly. The lectins were incorporated separately in artificial diet at a concentration of 10 to 160 µg ml-1 and fed adlibitum to the second instar larvae. Both the lectins were found to prolong the development period and significantly inhibited the pupation and emergence in a dose dependent manner. Total development period was found to be prolonged by 3.5 and 2.3 days in case of larvae fed on artificial diet containing A. intermedium (AIL) and A. wallichianum (AWL), respectively. LC50 values calculated on the basis of adult emergence came out to be 32.8 and 29 µg ml-1 for AIL and AWL, respectively. Both the lectins tested, were found to increase the activity of esterases as larvae proceeded from 24 to 72 hr of treatment. The activity of acid phosphatase decreased significantly in larvae reared on diet containing LC50 of AIL, while in case of AWL significant decrease was observed only at 72 hr of treatment. Alkaline phosphatase activity decreased significantly on treatment with both of these lectins. These results showed that AIL and AWL have promising anti-insect potential. So, lectin gene/s from either of these species can be cloned and subsequently can be employed to develop transgenics to control melon fruit flies specifically and insect pests in general. This approach could be used as a part of Integrated pest management (IPM) strategies.

Effects of Indian coral tree, Erythrina indica lectin on eggs and larval development of melon fruit fly, Bactrocera cucurbitae.

Present study was undertaken to investigate the influence of D-galactose binding lectin from Erythrina indica Lam. on the eggs and second instar larvae (64-72 hr) of melon fruit fly, Bactrocera cucurbitae (Coquillett). The lectin from E. indica seeds was extracted and purified by affinity chromatography using asilofetuin linked porous amino activated silica beads. The effects of various concentrations (0, 125, 250, 500 and 1000 .g ml-1) of lectin were studied on freshly laid eggs (0-8 hr) of B. cucurbitae which showed non-significant reduction in percent hatching of eggs. However, the treatment of second instar larvae (64-72 hr) with various test concentrations (0, 25, 50, 100 and 200 .g ml-1) of lectin significantly reduced the percent pupation and percent emergence of B. cucurbitae depicting a negative correlation with the lectin concentration. The LC50 (81.g ml-1) treatment significantly decreased the pupal weight. Moreover, the treatment of larvae had also induced a significant increase in the remaining development duration. The activity of three hydrolase enzymes (esterases, acid and alkaline phosphatases), one oxidoreductase (catalase) and one group transfer enzyme (glutathione S-transferases) was assayed in second instar larvae under the influence of LC50 concentration of lectin for three exposure intervals (24, 48 and 72 hr). It significantly suppressed the activity of all the enzymes after all the three exposure intervals except for esterases which increased significantly.