Biological Control of The White Cochineal Parlatoria Blanchardi (Hemiptera - Diaspididae) by Using Coccidiphagous Ladybirds and Biopesticides in Palm Groves of The Region of Ouargla (South-East Algeria)

Abstract

The white cochineal of the date palm is a very serious pest in the palm groves of the Ouargla region (South-East Algeria). Our attempt at biological control of this pest was based on the use of two coccidiphagous ladybirds Pharoscymnus ovoideus and Pharoscymnus numidicus and aqueous extracts of two Saharan plants Solenostemma argel and Azadirachta indica with two doses in two palm groves in the Ouargla region. The results obtained are very encouraging. White cochineal infestation rates of treated plants decreased considerably especially for the high dose of two treatments. The infestation rate decreased from 52.54% to 35.49% with P.ovoideus (120 ladybirds/tree) and from 54.03% to 18.88% with Neem extract (dose 5%), to 11.01% with Argel extract (dose 7.5%). The two ladybirds and the two extracts used showed highly significant differences (P=0.000), as did the two doses used (P< 0.0001). Our control attempt also showed an efficiency that increased with the increase of the dose used. It is 0.119±0.20 with the low dose of P. ovoideus to reach an efficiency of 0.324±0.23. For the extract-based treatments, the highest efficacy was recorded with the high dose Argel (0.812±0.22). It should be noted that the low doses used for both treatments gave insignificant results compared to their controls with the high doses, which showed very high significant differences with P=0.000 for the ladybird releases and P<0.0001 for the high doses of the water extracts.