DIAPAUSE AND PARASITISM OF THE SUGAR BEET LEAFMINER, PEGOMYA MIXTA VILLENEUVE (DIPTERA: ANTHOMYIIDAE), PUPAE REARED FROM CERTAIN CHENOPODIACEOUS HOST PLANTS AT GIZA | ||||
| Egyptian Journal of Agricultural Research | ||||
| Article 7, Volume 86, Issue 2, July 2008, Page 509-526 PDF (4.87 MB) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/ejar.2008.204856 | ||||
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| Author | ||||
| SAMER A. EL-SERWY | ||||
| Plant Protection Research Institute, Agricultural Research Center, Dokki, Giza, Egypt | ||||
| Abstract | ||||
| Leaves infested by the sugar beet learminer, Pegomya mkta Villeneuve (Diptera: Anthomyiidae) were collected from untreated sugar beet, Beta vuVaris L, spinach, Spinacia oletacea L., goosefoot, Chenopodium morale L and wild beet Beta vu/pans var. petennis during the period from November, 2004 to April, 2005 and with Chard, Beta vu&atis var. tide L. and mangold, Beta vuglatis var. niOtis during the same period in 2005 and 2006 in the farm of the Agric. Exp. Sta., at Giza. Rate and Incidence of diapause and parasitism and emergence of flies and parasitoids were determined. The overall mean of diapause was higher 49.3% (2004-2005) opposed to 38.5% (2005- 2006). Parasitism followed the same trend with 45.6% versus to 42.1% in the same seasons. Rate and incidence of dlapause and parasitism were highly variable among puparia reared from the different chenopothaceous host plants. The prevalence of higher general rates of diapause ( 67, 39.6 and 29.3%) and parasitism (77.3, 41.1 and 40.3%) were recorded on puparia reared from wild beet, goosefoot and sugar beet, whereas 55.1% (diapause) and 34.5% (parasitism) were attained on spinach puparia. Rate of diapause ranged between (0- 36.9%) and (10.6- 42.5%) on pupae developed from infested leaves of sugar beet and goosefoot in 2004- 2005 and 2005- 2006, but decreased from 64.6 to 45.7% and from 67.6 to 64.7% for those reared from spinadi and wild beet In the same period. However, parasitism ranged between (31.9- 37.2%), (38.7- 64.9%) and (52.983.1%) on parasitized puparia collected from spinach, goosefoot and wild beet in 2005- 2006 and 2004- 2005, but increased from 39.1% to 40.6% on sugar beet puparia from the first to the second season one. In both seasons, puparia went into aestivation (summer diapause) during February- April, but 1.3% entered hibernation (overwinter diapause) during November-January in 2005- 2006. Aestivated puparia started at rates of 21.9 and 41.8% in February, increased to 27.6% and slightly decreased to 37.5% in March and reached the highest rates 84.8 and 70.7% in April of 2005 and 2006, respectively. Synchronization was found between the timing of the highest percentages of emerged flies about (92 and 91%) and parasitoids (91 and 79%) In November of 2005 and 2006. The huge numbers of emerged parasitoids occurred with the high rates of parasitism 78.9 and 62.8% In November, 2004 and 2005. Such synchronization was found In 2004- 2005 active season, but was lost in the second one. In April of 2005, the highest percentages of emerged parasitoids and flies were 70.8 and 43.2%, but were 34.2 and 49.4% in January and April in 2006. To prevent and promote parasitoids, insecticides must be entirely avoided, agricultural practices i. e. deeply plowing, destruction alternative host weeds, hand pick and destroying infested mined leaves weekly before the larvae drop to the soil and dropping kerosene into water irrigation in a rate of 30 liter / feddan (4200 m2) reduce the population size of P. mixta and largely solving the likelihood and severity of leafminers problems in sugar beets. | ||||
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