INSECT PESTS OF DATE PALM TREES IN NORTHERN SINAI, EGYPT
EI-Sherif, S.I!, Elwan, E. A.2and Abd- EI- Razik, M. I. E.3 ABSTRACT
The Insect pests attacking date palm trees at AL-Arish region, Northern Sinai, Egypt, were surveyed throughout two successive years. Survey covered existing insect species, stage(s) causing damage, frequency of occurrence, period of occurrence and attacked plant partes). Eleven insect pests belonging to nine families from the orders Isoptera, Homoptera, Lepidoptera and Coleoptera were recorded. The most dominant and economically important pests were two scale insects (Parlatoria
blanchardii, and Phoenicococcus marlattU, a mealy bug (Dysmicoccus brevipes), the lesser date moth (Batrachedra amydraula) and the termite Psammotermes hypostoma. Accidental attacks of desert locust (Schistocerca gregaria) were of rare occurrence especially on offshoots. Fermented or
decayed damaged plant parts hosted Drosophila larvae and/or adults. Additional Index Words: date palm, insects, survey.
Cultivation of date palms in Egypt goes back to thousands of years. Approximately seven million fruiting palm trees are grown in Egypt in both the Nile valley and the desert. More than two hundred thousand fruiting palms grow in Sinai peninsula most of which occur in Northern Sinai particularly at AL-Arish region. Beside their high nutritive value, dates represent a main source of income for a wide sector of desert inhabitants.
Northern Sinai is, still, a relatively virgin ecosystem with almost no or very limited environmental disorder. It is quite essential, therefore, to maintain such naturally balanced system and restore its biodiversity. A basic step in that respect is to conduct continuous surveys of existing flora and fauna. As any other plant, date palms are, wherever grown, subject to infestation with a variety of insect pests. Such infestations may reflect serious damage on palms growth and, subsequently, cause considerable quality and quantity yield losses. In an effort to contribute to the knowledge
on the insect fauna associated with date palms, (the dominant tree in Northern) Sinai, the present investigation was aimed. Insect pests attacking the different parts of date palm trees at AI-Arish region were surveyed.
Surveys of date palm insects were previously reported nom Libya (Martin, 1958;EL-Haidari, 1981; and Bitaw and Ben saad, 1990), Egypt (Bodenheimer, 1923), Palestine (Ben Dov, 1985), Iraq (Buxton, 1920; and EL-Haidari et al. 1981), Qatar (EL- Haidari, 1981 and AL Azawi, 1986), Kuwait, Bahrain and United Arab Emirates (EI- Haidari, 1981), Sultanate of Oman (Aly and Elwan, 1995), Saudi Arabia (falhouk, 1982; and Hammad and Kadous 1989), Yemen (EI-Haidari, 1981), Pakistan (Sharif and Wajih, 1982) and California, U.S.A. (Cook, 1914).
MATERIALS AND METHODS
Survey of the insect pests attacking date palm trees in Northern Sinai, Egypt, was carried out at AI-Arish region, ca. 150 Km. east of Port-Side city, throughout two successive years nom March 1994 until February 1996. Several palm growing locations, scattered all over the region, were inspected for insect infestations once every month. At any selected location, 5 random trees-together with their offshoots-were carefully examined. Inspection covered all plant parts (e. g. roots, stem, leaflets, leaf mid-rib, spathes, female flowers and ftuits). Any existing insect stage(s) or infestation symptoms were identified on-site as far as possible. In case of uncertainty, samples of the occurring stage(s) were transferred in suitable containers to the laboratory for proper identification. Laboratory identification of the specimens was made either under the stereoscopic binocular or after mounting on microscopic slides. Whenever further identification assistance was required, the specimens were referred to the appropriate taxonomist(s) .at the Entomological Collection Division, Plant Protection Research Institute, ARC, MOA, Dokki, Giza, Egypt. Monthly examination of the trees further included an arbitrary evaluation of the nequency of occurrence of the surveyed insects (as rare, nequent or common). The period of occurrence of every surveyed insect pest was also approximately determined.
RESULTS AND DISCUSSION
A list of the insects recorded on date palm trees at AI-Arish region, Northern Sinai, Egypt, is given in Table 1. The upper section of this table shows that trees were subject to infestation with 11 insect pests belonging to
-9 families from the orders Isoptera (1 species), Homoptera (3 species), Lepidoptera (3 species) and Coleoptera (4 species). The lower section of the
. same table indicates that, in additionto the above-mentionedinsectpests,
few nymphs and adults of desert locust Schistocerca gregaria (Forskal) (Acrididae: Orthoptera) occasionally visited date palms, especially young offshoots, between March and October. Larvae and adult flies of Drosophila
melanogaster Meigen. (Drosophilidae: Diptera) were also seen during
autumn (September-November) on the fermented fruits primarily attacked with other pests. Surveys of date palm tree insects in the different countries refer to the occurrence of2 species in California, D.S.A. (Cook, 1914),25 species in Iraq (Buxtan, 1920),2 species in Egypt (Bodenheimer, 1923), 11 species in Bahrain, DAB, Kuwait, Qatar and Yemen (EI-Haidari, 1981),6-20 species in Saudi Arabia (Talhouk, 1982 and Hammed and Kadous, 1989), 7 major species in Pakistan (Sharif and Wajih, 1982) and 17 species in Oman (Aly and Elwan, 1995).
1- Common pests:
Information Table 1 reveals that the most common and economically important insect pests on date palm trees at AI-Arish region were the termite
Psammotermes hypostoma (Desneux) (Rhinotermitidea: Isoptera), the
parlatoria date scale Parlatoria blanchardlii (Targioni- Tozzetti) (Diaspididae: Homoptera), the red date scale Phoenicococcus marlatti Cockerell (Phoenicococcidae: Homoptera), the pineapple mealy bug
Dysmicocccus brevipes (Cockerell) (Pseudococcidae: Homoptera) and the
lesser date moth Batrachedra amydraula Meyrick (Momphidae: Lepidoptera).
P. hypostoma termite workers occurred on all tree parts all the year
round and considerably affected the palm. Termite workers mine into the stems and frond bases of weak palms and build sand or mud- covered galleries on the outside of the stem.
All stages of the scale P. blanchardii occurred on the leaves, spathes and fruits from early spring until late autumn and caused noticeable damage to them. Cook (1914) reported P. balnchardii on date palm trees in California and Arizona, U.S.A. Bodenheimer (1923) recorded the same species on date palms at AI-Arish (Sinai), Egypt. Batra and Sohi (1976) mentioned that P. blanchardiCis an important pest on date palm trees in India. P. blanchardii has also been reported on date palms from Yemen
(El-Haidari, 1981), Pakistan (Sharif and Wajih, 1982) and Saudi Arabia (Talhouk , 1982).
The different stages of P. marlatti were found on the leaves and aerial roots from March until December and oftenly destroyed invaded plant parts. In California and Arizona, D.S.A., P. mar/atti is a serious pest and obstacles successful date culture (Cook, 1914 ). It also attacks date palms in Sinai and Transjordania (Bodenheim~r, 1923). The same pest has been reported from Bahrain, Qatar and Yemen (EI-Haidari, 1981) and Saudi Arabia (Hammad and Kadous, 1989).
Nymphs and adult females of the mealy bug D. brevipes were seen in large numbers on or among the aerial roots from April until January. Infested trees were weak and their fruit yield decreased markedly. Ben-Dov (1985) stated that D. brevipes is a major pest on the roots of date palm offshoots in Palestine.
Larvae and adults of the date moth B. amydraula attacked fruits particularly throughout the fruit growing period between April and July. Infested fruits were totally or partially destroyed, and mostly fell to the ground before full ripening. In Libya, Qatar and Saudi Arabia, the larvae of
B. amydraula_attack date fruits (Martin, 1958; EI-Haidari, 1981; and Hammad and Kadous 1989).
2- Frequent pests:
The insect pests of frequent occurrence (Table 1) on date palm trees at AI-Arish region were the greater date moth Arenipses sabella Hampson (Pyralidae: Lepidoptera), the almond or fig moth Ephestia cautella (Walker) (Pyralidae: Lepidoptera), the date stone beetle Coccotrypes dactyliperda (Fabricius) (Coleopteran: Scolytidae), Phonapate frontalis Fahraeus and
Phyllognathus excavatus_Forster(Scarabaeidae: Coleopter).
Larvae of A. sabella attacked spathes and fruits from March till October. Their damage resembles that caused by B. amydraula. Hussain (1974), Hammad and Kadous (1989), Bitaw and Ben Saad (1990) and Aly and Elwan (1995) coincided that A. sabella bores into the fronds, spathes and bunches of date palm trees in Iraq, Saudi Arabia, Libya and Oman, respectively.
--E. cautella larvae and adult moths attacked ripe fruits during autumn
(September-December) and induced moderate to high quality and quantity fruit yield losses. It has been reported as a major insect pest on date fruits in Libya (Martin, 1958) and Egypt ( EI-Saeady and Abad el salam, 1982).
C. dactyliperda larvae bored into fruit stones from the beginning of fruiting season till its end (April-December). Female beetles penetrate into unripe date fruits and lay their eggs on the seeds. Emerged larvae penetrate into the seed itself and several generations may be completed within the fruit. Such damage occurs in several countries including Egypt (Willcocks, 1914), D.S.A. (Linsley, 1945), Libya (Martin, 1958), Iraq (Thiab Al Hafidh
et al., 1981), Saudi Arabia (Hammad and Kadous, 1989) and Greece
(Vassilaina et al., 1986).
The Larvae and adult beetles of P. frontalis excavated into the leaf mid-ribs as well as fronds all the year round. Larvae and adults fed on or . tunneled into the leaf mid-ribs and/or aerial roots in spring, summer and autumn. In Libya, the adult beetles of P. frontalis excavate into the mid-ribs and fruit bunches of the date palm tree (Bitaw and Ben Saad, 1990). P.
excavatus also bores into the roots.
3- Rare pests:
In addition to the afore-mentioned 5 common and 5 frequent inset pests, date palm trees in the study region were subject to rare infestation with the larvae and adult beetles of the Bostrychid Enneadesmus trispinosus Oliver (Coleoptera : Bostrychidae) which infested into leaf mid-ribs and female flower fronds all the year round. E. trispinosus beetles bore into the mid-ribs of date palm leaves and their fruit bunches in Libya (Bitaw and Ben Saad, 1990).
4- General remarks:
In spite of the fact that, at least, 10 insect pests of variable economic importance (common and frequent species) were recorded on date palm trees at AI-Arish region no natural enemies were associated with them except for an unidentified parasite, mostly Aphytis sp. (Aphelinidae: Hymenoptera), parasitizing upon the parlatoria scale P. blanchardii.
Surveyed date palm insect pests may be classified according to feeding behaviour into 5 groups including: 3 sap suckers (P. blanchardii, P. marlatti
and. D. brevipes), 4 borers (A. sabella, E. trispinosus, P.frontalis and P.
excavatus), a termite (P. hypostoma), a foliage feeder (S. gregaria) and 3
fruit destroyers (B. amydraula, C. dactyliperda and E. cutella). Special attention ought to be paid to, at least, restore the current status of insect pests on date palm trees in Northern Sinai. Such attention has to concentrate on two main strategies. One is the protection from introduction of any new pests to the region particularly through prevention of offshoots coming from outside the region or the country. The second is avoiding, as much as possible, using insecticides for combating date palm insects and relying-instead-on the various available non-chemical pest control measures to maintain the still existing more or less naturally balanced agroecosystem of the region.
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Table 1: Insects recorded on date palm trees at AI-Arishregion, Northern Sinai, Egypt.
Attacked Period of
No. Species Family Order Status Frequency Stage(s) plant partes) occurrence
1 Psammotermes hypostoma (Desneux) Rhinotermitidae Isoptera P C W AI Jan.-Dec.
2 Parlatoriablanchardii(Tragioni-Tozzetti) Diaspididae Homoptera P C As Lb,Lt,Ff, Ft & Sp Mar.-Dec.
3 Phoenicococcusmarlatti Cockerll Phoencococcidae Homoptera P C As Lb,Lt,Mr&Rt Mar.-Dec.
4 Dysmicoccusbrevipes (Cockerel!) Pseudococcidae Homoptera P C N&A Rt Apr.-Jan.
5 Batrachedraamydraula Meyrick Momphidae Lepidoptera P C L Ff&Ft Apr.-Jul.
6 Arenipses sabella Hampson Pyralidae Lepidoptera P F L Ft&Sp Mar.-Oct.
7 Ephestia cautella (Walker) Pyralidae Lepidoptera P F L&A Ft Sep.-Dec.
8 Coccotrypes dactyliperda (Fabricius) Scolytidae Coleoptera P F L&A Ft Apr.-Dec.
9 Phonapate frontalis Fahraeus Bostrychidae Coleoptera P F L&A Ff&Mr Jan.-Dec.
10 Enneadesmus trispinosus Olivier Bostrychidae Coleoptera P R L&A Ff&Mr Jan.-Dec.
11 Phyllognathusexeavatus Forster Scarabaeidae Coleoptera P F L&A Lb&Rt Apr.-Dec.
12 Schistocercagregaria (Forskal) Acridide Orthoptera V R N&A Lt,Ft&Os Mar.-Oct.
13 Drosophilamelanogaster Meigen. Drosophilidae Diptera Sy R L&A Ft Sep.-Nov.
C: common F: frequent R: rare
A: adult As: all staaes L: larva N: nvmoh W: worker
AI: all Darts Lb: leaf base Lt: leaflet Ff: female flower Ft: fruit
Mr: mid- rib Os: offshoots Rt: root So: soathe St: stem