A study of fruit position and abiotic factors on melon fruit fly Zeugodacus cucurbitae Coquillett (Diptera: Tephritidae) infestation in cucumber

Abstract

The melon fruit fly (Zeugodacus cucurbitae Coquillett) is a major economic insect pest of Cucurbitaceae crops that causes immense damage to the quality and quantity of agricultural products. Because biotic and abiotic factors directly affect insect population growth and infestation, this work aimed to study the fruit position on the cucumber tree and abiotic factors of the melon fruit fly in terms of both population and subsequent damage. Our study comprised two growing years in Thailand’s Khon Kaen province; November 2018 to February 2019 and October 2019 – January 2020. The results from the first growing year showed 136.81±14.83 adult melon fruit flies/plant and 12.33±22.72 damaged cucumbers from fruit located in the middle position of the cucumber tree; which was significantly different (P<0.05) from the number of melon flies found in the upper and lower positions on the tree at 106.50±6.15 and 102.29±7.87 fruit flies/plant, respectively; and the number of damaged cucumbers at 3.65±8.75 and 4.16±10.95 fruits/plant, respectively. The results in the second growing year resembled those of the first year. The melon fruit fly began to migrate into the plots in the third week after planting and increased to its peak numbers in the fifth and sixth weeks (flowering-fruiting period), recording 161±16.74 and 186±16.79 fruit flies/10 traps in the first growing year, respectively, and 178±19.62 and 159±5.83 fruit flies/10 traps, respectively, in the second growing year. The correlation coefficient (Correlation, r) between the number of melon fruit flies and such abiotic factors as temperature, relative humidity, and rainfall in the first growing year ​​were -0.47, 0.19, and 0.29, respectively. In the second growing season, the values were -0.32, 0.69, and 0.01, respectively. Results from this study help to determine the preference of melon fruit fly to fruit position on the cucumber tree and the appropriate time to control