Population Dynamics of Citrus Leafminer, Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae) and Its Parasitoids on Mandarin Trees in Sharkia Governorate, Egypt

Abstract

The present work was conducted to study the population dynamics of citrus leafminer (CLM) and its associated parasitoids on mandarin trees during two successive years of 2013-14 & 2014-15 all in relation to climatic factors [temperature and relative humidity (R. H.)]. The citrus leafminer larval population had 6 peaks of abundance on mandarin trees in each studied year. The higher population peaks of the pest were noticed during two main periods. The first period was in late May and the second period observed in late August and the middle of September. Generally, springtime is considered the most abundant season for Phyllocnistis citrella infestation followed by either summer or autumn seasons. In winter, there is a complete absence of CLM infestation. There is a positive relationship between CLM population abundance and both temperature and R.H.%. The associated parasitoids Semielacher petiolatus (Girault) and Cirrospilus ingenuus (Gahan) had five peaks of abundance during each studied year. The highest parasitism was 42.5% at the beginning of August in 2013-14 and 19.2% in the middle of September in 2014-15. The effect of a combination of parasitoids and climatic factors on CLM population was presented as explained variance (E.V.) which was 36.9 % in the first and 34.7% in the second studied year.