Host Preference and Biology of Potato Tuberworm, Phthorimaea operculella (Zeller) (Lep.:Gelechiidae), on Leaves of 12 Potato Germplasm in Greenhouse

Document Type : Research Article

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Abstract

The potato tuberworm, Phthorimaea operculella (Zeller), is a major pest of potato in both store and field. In this research, host preference, biology and life table parameters of this pest were studied on leaves of 12 potato germplasm including seven commercial cultivars (Agria, Ausonia, Sprit, Satina, Savalan, Kondor, Morene) and five Iranian clones (PI396156-5, PI397045-15, PI397097-2, PI397082-2, PI396124) in a greenhouse at 25 ± 2ºC, 60 ± 5% RH and photoperiod 14:10 (L:D). In choice experiments, one potted plant from each of 12 tested germplasm were placed in a circle inside the cage (1×1×1.5 meter), then 12 pairs adults (one-day-old) were released inside the cage. After one week, numbers of mines per plant and number of live larvae per plant were counted. The results indicated that the lowest percentage of injured leaflets and the lowest live larvae (5.1, 4.8) were observed on PI397097-2 among the tested germplasm. In no-choice experiments, development time of larvae and pupa, survival rate of larvae and pupa, weight of pupa and life table parameters of the potato tuberworm reared on the leaves of each of 12 tested germplasm were determined. The development time of larvae, pupa and generation time on PI397097-2 were significantly higher than those on the other studied germplasm. The lowest weight of pupa, the lowest survival rate of larvae and the lowest intrinsic rate of increase (0.076) and innate rate of increase (1.079) were observed on PI397097-2. Therefore, it can be concluded that clone PI397097-2 is the least suitable for the potato tuberworm among the tested germplasm.

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