Determination of damaged leaf area and physiological responses of melon plants submitted to different infestation levels of Liriomyza sativae

Abstract

The leafminer Liriomyza sativae (Diptera: Agromyzidae) is one of the main pests of melon crop (Cucumis melo) in the Brazilian semiarid. The aims of this study were to determine the damaged leaf area and assess the physiological responses of melon plants submitted to different levels of infestation per larvae of L. sativae. The study was carried out in a greenhouse, using plants of melon of the cultivar Iracema (yellow melon). The design utilized was completely randomized, with five treatments [control (no infestation in the leaves) and four infestation levels (1; 10; 20 and 30 larvae per leaf)] and 10 replications (melon plants). Initially we evaluated the physiological aspects: photosynthetic rate (µmol CO 2 /m 2 /s), stomatal conductance (mol H 2 O/m 2 /s) internal CO 2 concentration (µmol CO 2 / m 2 ) and leaf transpiration (mmol H 2 O/m 2 /s). After the measurements of physiological aspects, the evaluated leaves of each plant were cut close to the petiole and scanned individually with a measuring scale on the side, being the determination of the damaged leaf area performed with the aid of software for processing and analysis of images. The averages of damaged leaf area observed were of 1.2; 6.3; 19.6 and 40.8 cm 2 for infestations of 1; 10; 20 and 30 larvae/ leaf respectively. In relation to the physiological aspects, the rate of photosynthesis, stomatal conductance and transpiration significantly decreased with the increase of leafminer larvae per leaf. The internal CO 2 concentration increased with the increase in the number of larvae per leaf.

Environmental variables influence the developmental stages of the citrus leafminer, infestation level and mined leaves physiological response of Kinnow mandarin

“…Significant reductions in net assimilation rate, stomatal and sub-stomatal conductance were observed in mined (1–8 months) old leaves compared to non-mined/intact leaves in the present work. Costa et al 16 also reported low photosynthetic activity in leafminer damaged melon plants, which also confirmed low photosynthetic activity in mined leaves as recorded in this study. Dented chloroplasts in mined leaves reduce carbon assimilation 80 and respiration rate 87 due to low carbon accumulation or CO 2 emissions in spongy parenchymal cells 88 which reduce sub-stomatal conductance and ultimately delay the physiological response of damaged leaves 89 .…”

“…Leafminer infestation directly reduced yield and caused stunted plant growth and an early drop of infested leaves on all three vegetative flushes 13 . Henceforth, mined leaves have imperfect physiological response 14 with low photosynthetic activity 15 , 16 and also possess less polyphenols and antioxidant activity 17 by directly reducing on-tree age of infested leaf.…”

Sources and Inheritance of Leafminer Resistance in Yellow Melon Accessions

“…The main damage caused by leafminers on melon is from larvae feeding on the leaf mesophyll tissue that create galleries or mines that reduce the photosynthetic area of the plant, causing the reduction of production and fruit quality (ARAUJO et al, 2013;COSTA et al, 2017).…”

Toxicity of insecticides used in melon crop to Opius scabriventris, a natural parasitoid of Liriomyza sativae

“…The leafminer Liriomyza sativae (Blanchard, 1938) (Diptera: Agromyzidae) is an important pest in the melon crop (Cucumis melo L., 1753 ) in Brazil (Araujo et al, 2013;Ferreira et al, 2017). The larvae of this agromizid consume the leaf mesophyll, causing the reduction of the plant photosynthetic capacity and the total soluble solids content ( o Brix) of the fruit (Araujo et al, 2013;Costa et al, 2017).…”