TY  - JOUR
JF  - Acarologia
T1  - Induced defense in healthy date fruits neighboring Oligonychus afrasiaticus-infested bunches
VL  - 66
IS  - Suppl
SP  - 251
EP  - 251
PY  - 2026
SN  - 0044-586X
SN  - 2107-7207
PB  - Les Amis d'Acarologia
AU  - Samah, Ben Chaaban
AU  - Monia, Jemni
AU  - Sihem, Ben Maachia
AU  - Ibtissem, Mahmoudi
AU  - Kamel, Mahjoubi
UR  - https://doi.org/10.24349/27gj-iwm3
DO  - 10.24349/27gj-iwm3
DA  - 2026-07-20
ET  - 2026-07-20
KW  - Date palm
KW  - Induced resistance
KW  - Oligonychus afrasiaticus;Healthy fruits
KW  - Phenolic compounds
AB  - In date palm orchards, bunches heavily infested by Oligonychus afrasiaticus and covered with dense webbing may coexist on the same palm with neighboring bunches that remain visually healthy and apparently uninfested. This study aimed to determine whether these healthy fruits already express biochemical and structural traits consistent with a systemic induced defense response. Visually healthy date fruits were collected from bunches borne by heavily infested palms, lightly infested palms, and non-infested control palms. Fruits were analyzed for physicochemical, biochemical, and color parameters in order to compare healthy fruits associated with infested palms against fruits from control palms. Healthy fruits associated with heavily infested palms showed clear shifts compared with controls. Flavonoid content increased from 5.85 to 8.34, total polyphenols from 41.32 to 68.82 mg/100g FW, and exocarp firmness from 23.79 to 29.17 N. Sugar content was also higher in fruits from infested palms (7.17 g/100g FW in heavily infested palms and 7.93 g/100g FW in lightly infested palms) than in controls (3.93 g/100g FW). In contrast, pH decreased from 5.8 to 5.4 and water content from 78.6 to 72.3%. Color traits were affected, especially chroma, which increased from 7.75 in controls to 38.57 in fruits from heavily infested palms. Principal component analysis clearly separated the groups, with flavonoids, polyphenols, sugars, exocarp firmness, and chroma as the main discriminating variables. These results support the hypothesis that infestation of some bunches by O. afrasiaticus may trigger a systemic defense-like response in the palm, allowing neighboring still-uninfested bunches to acquire a protective biochemical and structural status. Phenolic compounds, firmness, and color traits therefore appear to be promising markers of induced resistance in date palm.
ER -