Abundance ofSesamia nonagrioides(Lef.) (Lepidoptera: Noctuidae) on the Edges of the Mediterranean Basin

Abstract

Organisms inhabiting seasonal environments are able to synchronize their life cycles with seasonal cycles of biotic and abiotic factors. Diapause, a state of low metabolic activity and developmental arrest, is used by many insect species to cope with adverse conditions.Sesamia nonagrioidesis a serious pest of corn in the Mediterranean regions and Central Africa. It is multivoltine, with two to four generations per year, that overwinters as mature larva in the northern of the Sahara desert. Our purpose was to compare the response of theS. nonagrioidespopulations occurring in the broader circum-Mediterranean area, with particular attention to the diapause period and the different numbers of generations per season. To this end, we tried to determine whether populations in the area differ in their response to photoperiod and whether we can foresee the number of generations in different areas. We present a model for predicting the occurrence of the critical photoperiod according to latitude and temperature and the spread ofS. nonagrioidesin the circum-Mediterranean countries. Responses of populations to short-day length suggest that the spread of the species is associated with a gradual loss of diapause in the southern areas, and that diapause incidence is positively correlated with latitude.

Managing maize under pest species competition: Is Bt (Bacillus thuringiensis) maize the solution?

“…The MCB is a cosmopolitan multivoltine species with a wide range of host plants, including maize (Kfir et al. , Eizaguirre and Fantinou ). It is considered to be the most important maize production pest in Spain and in other countries around the Mediterranean basin (Cordero et al.…”

“…). Since maize production areas have increased in these areas during the past, the pest has consequently expanded (Eizaguirre and Fantinou ). Larvae cause damage by tunneling into stems or the ear until pupation, weakening the plants and consequently reducing yield (Malvar et al.…”

“…). Economic losses accrued to MCB in Spain have not been fully quantified, since the injury is undistinguishable from that caused by ECB (Eizaguirre and Fantinou ). The damage caused by MCB can reach 30% of the maize yield depending on the date of sowing and on the plant development stage when attacked (Butrón et al.…”

“…The MCB, is here used as an example of a primary pest due to its historical importance and present susceptibility-99%-to the Cry1Ab toxin (González-Núñez et al 2000, Farinós et al 2011. The MCB is a cosmopolitan multivoltine species with a wide range of host plants, including maize (Kfir et al 2002, Eizaguirre andFantinou 2012). It is considered to be the most important maize production pest in Spain and in other countries around the Mediterranean basin (Cordero et al 1998, Malvar et al 2002.…”

“…It is considered to be the most important maize production pest in Spain and in other countries around the Mediterranean basin (Cordero et al 1998, Malvar et al 2002. Since maize production areas have increased in these areas during the past, the pest has consequently expanded (Eizaguirre and Fantinou 2012). Larvae cause damage by tunneling into stems or the ear until pupation, weakening the plants and consequently reducing yield (Malvar et al 1993).…”