Screening of cactus resistant varieties for the cochineal scale Dactylopius opuntiae (Cockerell) (Hemiptera: Dactylopiidae) and observations on its predator Hyperaspis trifurcata (Coleoptera: Coccinellidae) in Jordan : tesi di master
Out of 47 visited locations in northern Jordan, this study showed that after the first report of the cochineal scale in 2018, the distribution continued to spread southward. The highest infestation being in Al-Suleikhat area in 2021. This study also highlighted the importance of resistant varieties in IPM measures against the cochineal scale. Therefore, 125 different cactus accessions obtained from the International Center for Agricultural Research in Dry Areas (ICARDA) were assessed for their resistance against the pest. All the accessions (Unknown 120 and Unknown 122 from Syria, Opuntia robusta 1280 from Argentina and Opuntia robusta 200146 from Brazil) have shown 0% infestation rate both in vivo and under controlled conditions.
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On the other hand, the highest susceptibility was recorded for Zastron 4 and M3 Bianca di Macomer from Italy and 40-Tronzar and GS from Tunisia with an infestation rate > 90%. Additionally, the predator Hyperaspis trifucata lifecycle duration took an average of 29.3 days in vitro (first larva to adult). H. trifurcata larvae and adults were aggressive feeders; they consumed up to 150 D. opuntiae nymphs in two days. Furthermore, the generation duration of the pest was equal to 36.3 ± 2.59 days under a temperature of 27°C and 70-80% of RH.
