Olive psylla
The scientific name : Euphyllura olivina
the family : homoptera
Symptoms of the disease :
The insect secretes a white waxy substance in which the infected parts are collected. It secretes honeydew that causes the growth of black fungi.
This pest attacks the buds and young clusters of olive trees and causes severe damage to the fruits (30%) and flowers (60%).
Description of the insect: Its length is (3 mm) and its color is yellowish-brown or greenish-brown. There are scattered yellow dots on the translucent white wings, and these dots are not present on the back wings. The nymphs’ body has wax threads that cover it completely.
The causes of disease :
Insect biology is closely linked to the biology of the host plant and climatic conditions
Due to high temperatures and the olive growth cycle (the gradual slowdown of vegetative growth), the second adult summer generation appears in the period from June to September and is the most dangerous of the generations.
Conditions suitable for the spread of the disease :
The results showed that the ability of females to lay eggs decreases when the temperature exceeds 20 degrees Celsius. In particular, there was a complete inhibition of ovarian activity at 32°C resulting in no eggs being laid at all.
Disease development cycle :
E. olivina can complete three life cycles on olive trees.
Adults of all three generations are present continuously during the year. Adults spend the months from July to September in a period of reproductive diapause, which has been verified by studying gamete formation in females.
The second generation is the most dangerous because it can cause some yield losses.
Adults emerge in June and, after an obligatory summer dormancy, remain dormant from September through January and March.
Losses of disease spread
It is a great danger to the olive tree. They feed on flowers and cause damage, resulting in the loss of the olive crop.
Due to the release of waxy secretion and honeydew, it can cause aesthetic damage to ornamental hedges
Control strategy
Preventive measures to prevent the occurrence of the disease
Taking care of the necessary fertilization operations.
Provide sufficient amount of irrigation.
Cleaning the area around trees from weeds.
Pruning olive trees and removing infected branches.
Chemical and organic control recommendations
Biological control by the Mediterranean parasite Psyllaephagus euphyllurae
Encourage integrated control through the use of mating disruption, traps, and release of predatory insects or parasitoids
Extracting polyphenols from vegetable waste contributes to its use as a biopesticide
Spraying trees (at the end of April) and before the flowers open with dimethoate.
References
Del Bene, G., E. Gargani, and S. Landi. “Observations on the life cycle and diapause of Euphyllura olivina (Costa) and Euphyllura phillyreae Foerster (Homoptera Aphalaridae).” Advances in Horticultural Science (1997): 10-16
GUESSAB, A., et al. Population dynamics, seasonal fluctuations and spatial distribution of the olive psyllid Euphyllura olivina Costa (Homoptera, Psyllidae) in Algeria. Arxius of Miscel làniaZoològica, 2021, 19.
DEBO, Ali, et al. Efficacy of a hydroxytyrosol-rich preparation from olive mill wastewater for control of olive psyllid, Euphyllura olivina, infections. Crop Protection, 2011, 30.12: 1529-1534
LARIF, M., et al. New innovation in order to recover the polyphenols of olive mill wastewater extracts for use as a biopesticide against the Euphyllura olivina and Aphis citricola. Research on Chemical Intermediates, 2013, 39: 4303-4313.
Links :
https://www.jstor.org/stable/42881833
https://www.sciencedirect.com/science/article/pii/S0261219411002614
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