Annual Variation in Population of the Bean Fly Leaf miner, Melanagromyza Phaseoli (Tryon), Generation Numbers and Related Injury in Common Bean Fields

Abstract

Four experiments were conducted at Embaba, Giza Governorate by planting beans four times during 2011, 2012 and 2013 to assess the annual variation in population of Melanagromyza phaseoli attacking bean plants Phaseolus vulgaris (L.) in relation to certain climatic factors, synchronization of plant age with insect counts, generation numbers, and injury on plants. Obtained results cleared that adults and larvae of this fly attack plants as soon as seedlings emergence in all growing seasons. In spring 2011, adult females reached highest counts 1.17, 1.17 and 1.1 individual/ sweep at 12 th April, 10 th May and 7 th June, respectively. Their larvae reached highest 2.2 and 15.33 larvae/leaf at 26 th April and 31 st May. The highest tunnels number during season was 26.87 tunnel/leaf. In summer 2011, larvae reached highest counts 1.4, 29 and 2.3 larvae/leaf at 5 th July, 23 rd August and 20 th September at temperature 27.17, 29.84 and 27.97°C and relative humidity 54.14, 54.57 and 57.71%, respectively. During summer 2012, both adults and larvae reached its highest three times, larvae were 1.9, 4.87 and 7.2 larvae/leaf. Tunnels number was 11.07/leaf in highest case. Leaf miner population was rather low during winter 2012/2013. Capabilities of insect to produce progeny and to injure plants were discussed. Insect produced three generations/ growing season. Temperature and relative humidity revealed their presence inside the optimum range for the insect activity. Plant age had positive relationship with larvae counts in spring and summer seasons. Management program must be directed against insect during period 39-74 day of plant age.

Genetic Studies for some Bean Traits in Relation to Stability and Insect Infestations

“…Abd El-Salam et al, [31] found that leaf miner cause damage to faba bean plants during all life stages. Moreover, Salem et al, [18] revealed that larvae of Melanagromyza phaseoli (Tryon) reached its highest counts and highest percent of infested leaves during the season growth at 31 st May when temperature was 27.91°C and relative humidity was 43.86%. On the basis of aforementioned results, infestation of these insects reached its maximum percentage during the experimental seasons by 55.2% (aphid) and 85.9% (Leaf miners); when temperature ranged from 24.25 and 28.55°C; and relative humidity from 59.75 to 64.9% (Fig.…”

“…1) and plant age was between 10 th and 11 th weeks (Table 8). This refers that this period (10 th and 11 th weeks of plant age) was the most favorable and attractance for aphid and leaf miner infestation; with the range of abovementioned temperatures and relative humidity, so management program must be directed into insect during this period of plant age or during this ranges of climatic factors, Salem et al, [18]. Moreover, Talekar [32] indicated that adequate control of Agromyzids sp.…”

“…Since despite 100% plant infestation yield loss is barely 30% and the fact that this pest rarely kills plants, it is possible to develop bean cultivar tolerant to this pest. In Egypt, M. phaseoli insect was ignored and did not receive any attention from researchers until became dangerous on bean plants [18]. However, among the aim of this study was to assess the annual variation of this insect through different growing densities and seasons in relation to certain climatic factors, synchronization of plant age with insect infestation percentage on plant due to insect activity.…”