Archive \ Volume.7 2018 Issue 4

First Attempts to Repel Scale Insects Using Plant Extracts: Effect on The Date Palm Scale Parlatoria Blanchardi Targ. (Hemiptera: Diaspididae)

Mahfoud Babaousmail , Mohamed-Azzedine Idder , Abdellah Kemassi

Date palm, (Phoenix dactylifera L.), is a crop that plays a central role in the economy and the social life in the Middle East and North Africa. Date palm scale (Parlatoria blanchardi), is one of the most dangerous insect enemies of this crop. The aim of the present paper was to assess the repellent activity of some spontaneous plants against the crawlers of the first instar larvae of Parlatoria blanchardi.  Methanol extracts of Castor bean Ricinus communis, Bitter apple Citrullus colocynthis and Syrian rue Peganum harmala were subjected to a phytochemical screening. Next, a bioassay was conducted to test their repellent effect on the crawlers compared to the control. The results indicated the presence of Tanins, Alkaloids, Polyphenols, Flavonoids and Saponins in the three extracts, whereas Terpenoids were not detected. The repellent bioassay showed that the mean number of crawlers found in negative control leaflets was significantly higher P<0.05 than most of the extracts’ concentrations. Some concentrations of C. colocynthis and P. harmala, however, lost their efficacy after 11 days of treatment. Overall results may contribute to develop new strategies to control the scale insects’ populations not only by toxicity but also by repellency.