EFFECT OF DIFFERENT KINDS OF BUNCH COVERING ON DATE PALM FRUIT (PHOENIX DACTYLIFERA L.) MOTHS INFESTATION RATE

One of the most depreciatory damage on date palm fruit quality in Morocco is the dates infestation by moths (Ectomyelois ceratoniae). The percentage of infested dates is estimated between 1 to 4% in the field and can reach more than 70% during fruit storage. The objective of the present study is to prevent the responsible adult insect to reach the fruits through bunch covering on the trees. For this purpose, four palm trees, 15 years old from the ‘Najda’, ‘Bousthammi’, ‘Tademmamte’, ‘Bouslikhene’, ‘Admou’ and ‘Iklane’ cultivars grown in the same environment of the Zagora Date Palm Experimental Station, were carefully chosen and used to study the effects of 4 different kinds of cover bags including: jute cover, and net covers with meshes as small as 3.8, 1.7 and 0.15 mm². The experiment was established at early khalal stage in a complete randomized block design. Samples of 400 dates were harvested in early October and damages were determined by counting the number of infested fruits per sample. The results of this three-years experiment showed that the lowest infestation rates (less than 1%) occurred with net covers of 1.7 and 0.15 mm² meshes while the highest damages (4.1 and 4.5%) occurred with jute covers and control respectively. Analysis of fruits dimensions and weights showed no significant differences between all treatments. These results were demonstrated and verified on 16 palm trees of ‘Najda’ and ‘Jihel’ cultivars grown at some growers’ fields. These field experiments allowed dates production of less than 1% infestation rates. Accordingly, bunch covering with nets of 1.7 and 0.15 mm² meshes could be recommended to growers under similar conditions of the present study.