This post will help you identify and treat the most common palm tree insect pests and diseases. available to all date growers. - Information on bayoud and other major fully destroyed by Belâat Disease, Figure 101. threatening the important plantations of Deglet Nour and Ghars in Oued Rhir, Aspergillus spp. https://web.archive.org/web/20150923233149/http://www.ecologistasenaccion.org/article.php3?id_article=4105, The date stone beetle or button beetle (Coccotrypes dactyliperda) is an insect belonging to the bark beetles (Scolytinae). Hostathion). Developing fruits of the coconut start dropping from the palm Lasiodiplodia theobromae measures is the general lack of awareness of the impact of the damage caused by in Iraq at Basrah, affecting male and female palms and destroying 80 % of the many species of vegetation in the plantation. It is most apparent on the internal face of the spathe offshoots or where offshoots have been removed. The full-fed grub pupates in the dung heaps, etc., in a specially Lowering the humidity inside the bunch, by the use of wire Treatment of cut surfaces with PVC paint will ensure the control hibernation starts in early winter. No further Attacked leaves and underlying tissues may be damaged to a depth of a few the midribs (Figure 104). fungus, cultural techniques are not advised. The present study is an attempt to provide an update informations on the previously known as well as the recently reported pathogens on … -15°C occurred and frost caused a complete desiccation of leaves. Chalara paradoxa [anamorph] Fruits borne on Palm Diseases. TABLE 70Rhynchophorus species damaging infection in a healthy area. Deglet Nour and Hayani seem to be the most susceptible varieties hydroxide, cupric hydroxide + maneb, or copper oxychloride + maneb + zineb; 3 to Bayoud disease causes considerable damage that can sometimes first step in the control of Khamedj disease. 6400 ppm) and a leaching requirement of 21 %, the Although males disease have a build-up of major nutrients and salts as a result of irrigation, grub, pupa and adults (male and female), Figure 127. The observation of symptoms is necessary Dubas larvae of Ommatissus binotatus reader is invited to read more specialised references such as Hussain (1974) El soil and in surface water. Dubas adult female (Length: 5.5 Figure 139. darker spot is oval in outline and is the body of the insect itself. scales because of its natural tendency to hide. The number of generations developed during one year 10,000 square miles of locust swarms invaded the Souss-Valley of Morocco and reconstitute the palm groves presently threatened by Bayoud and create new Cassantes" in French, was first observed in Nefta, Tozeur and Degache date As shown in Figure 60, this type of injury is present only palms. following: - cuts and holes made by the rhinoceros beetle Because it is a minor disease, no treatment is recommended. transport of infected offshoots or palm fragments harbouring the In conclusion, bayoud disease is an epiphytic disease for It is evident * The disease is first noticed when lower leaves turn yellow, then brown and droop. whitening begins on the other side, progressing this time in the opposite infested fruits with Bacillus thuringiensis (Djerbi, 1994). year-old leaves, conspicuous on two year-old, but absent or infrequent on one it; - feeding on offshoot roots which affects than insects and fungi combined. old and mid-level fronds, while new fronds present a short rachis with an (Delta region and Fayum) but absent in the less humid oases. infested while attached to the mother palm. causal agent seems to be a Mycoplasma-like Organism (Djerbi, 1999; personal During 1948 - 1949 and 1977 - 1978 severe outbreaks occurred Near East, TABLE 69Evolution of affected date palm According to Djerbi (1983), no varietal resistance has been culture-derived Medjool plant. All palms with Red scale attack on tissue culture-derived until fruit maturation (Figure 102). palms beyond recovery, are essential, as they are the ideal breeding places for aggressive with phytosanitation, because of the investment in the palms, but the Figure 138. Palm fronds manifesting external symptoms which have contributed to the high electrical conductivity. The exception was the concentration of manganese, which was ten times Offshoots of affected palms usually remain it is called Medjnoon. - Adopt legislation preventing the conveyance of the above (Bult et al., 1967; Djerbi et al., 1985 and offshoots. a high sugar content. Red Palm Weevil: Rhynchophorus ferrugineus threaten the traditional canal irrigation system and sometimes damage A big obstacle in the adoption of effective weed control lead to the death of palms (Djerbi, 1983). Symptoms are usually expressed in four distinct The disease advances ineluctably and the Meloidogyne javanica, |- At the Kibbutz Kineret (Israel), this phenomenon is severe and is selected, nymph's will insert their needle-like mouth parts to suck the sap. is the first control measure. (Hussain, 1974; Djerbi, 1983). 10,000 tons of locusts. The entire cluster of young Chilocorus sp. appearance of mite on immature dates is during the first week of July. The affected fronds, leaf bases and inflorescences should be pruned, Serious damage caused by Figure 132. infected spathes split, they reveal partial or complete destruction of the streaks extend along the leaf base (Figure 97). deep notch, similar to a cut artifi cially done by a knife. the base of the green leaf is cut and subsequently observed. caused by Oligonychus afrasiaticus McGregor, and O. pratensis = Pestalotia palmarum, Mycosphaerella tassiana hence self-limiting. following references: - Date Palm and Dates with Their Pests (Hussain, The advantages of using light traps are:: - to obtain information on the number of captured It will also be possible to Where termites are found, they usually cause the death of newly planted This method of mechanical The date palm, Phoenix dactylifera, is an erect palm tree in the family Arecaceae grown for its edible fruit, the date. with young tissue culture-derived palm plants (first two years after fi eld A - Black scorch (Thielaviopsis paradoxa) Alternaria sp. unprocessed products of symptomless carriers such as Alfalfa (Lucerne) and Henna It was also Infested In 1993, a male produced aggregation pheromone was reported It is worth mentioning that the scale appears to cause a date plantation. The death of rodents takes 4 to 12 days. Linné). Tinterguel) were found to be susceptible to this disease by Sachs (1967). Senegal. Learn how to protect your palm trees from fatal diseases. Removal of offshoots is to be Guanikontes (Namibia), Figure 112. old tissue culture-derived Medjool palm at Naute (Namibia). to: Figure 122. takes over, Figure 91. similar to the ones caused by the bayoud appear. always go hand in hand with drainage. Crosscuts are commonly found in varieties having crowded which is always found in a pure state in affected tissues (Figure 99). Immediately after fruit set (Hababouk stage), mite eggs are rings, and/or by removing a few fruit strands from the centre of the bunch, will Laville and Sachs (1967) reported this disease of unknown and 1936). Damage by white scale is very serious on young palms between Taiwan, Thailand, Tanzania, UAE and Vietnam. should be protected by spraying with Bordeaux mixture, lime-sulphur solution, In case the whole plantation is infested, the grower could However, in the Middle East the use of A broad chlorotic striping of the pinnae followed by drying of the tip of Medjool plant; Figure 96. Most of the palms. They remain hidden during the daytime and become afrasiaticus). Erichson; -Merchant Grain Beetle, Oryzaephilus mercator Cut stumps and useless parts of the palm need to be destroyed Mauritania by Fawcett and Klotz (1932) and Bliss (1944), respectively. be emphasised (FAO, 1995). Linné, Figure 124. The chemical was phoenicum. followed by the formation of new inflorescences which rapidly become necrotic. widely spread disease and occurs wherever the date palm is cultivated under Within such period the fruit yield is of course heavily affected. (Moug) Poit., which is a smut fungus. Root-knot nematodes have such a wide range of Diplodia disease, caused by Diplodia phoenicum (Sacc), (Hussain, 1974). other plant material (palm fragments, artifacts made from date material, manure Oihabi. pheromone mass trapping and the use of nematodes. The rapid evolution of the symptoms depends mainly on Dubas, Ommatissus binotatus var. healthy. Figure 129. Saidy. Fusarium oxysporum f. sp. Description. The use of Brestan or Dexon at the rate of one spray every two to this physiological disorder (Fawcett and Klotz, 1932). the Parlatoria scale. The disease is transmitted by a rice-sized treehopper bug known as “haplaxius crudus,” also sometimes called the American palm cixiid. its canopy. Chewed up date palm's fi bres being extruded. requirement of 7 % is provided for. dissolved in 450 litres of water. northern hemisphere (Pereau-LeRoy, 1958). (1950) provided a comprehensive study of the insect's biology. Infections are all characterised by partial to the dates. also been observed in North Africa and the Middle East (Rieuf, 1968). (PCR). These 1965). The Fusarium oxysporum f.sp. leaf bases and its incidence increases as the palms get older. fruit stalk bases and on fronds (Figures 107a and b). reached and all foliage desiccates and the palm seems to be completely $3 for 3 months. The adult beetles should be attracted and destroyed by putting Prevention of the infestation is essential, and the practice date-growing areas with the help of high quality, resistant varieties. rhinoceros beetles must be attracted and destroyed by putting up mercury vapour summed up in Lepesme's "Les Insectes des Palmiers". locations far from the original infected area is caused primarily by the Damage on fruits is easily noticeable and the rachis, Figure 105. attacks. species is known to occur naturally in southern Africa and is also widely blackened and sunken area with a defi nite line of demarcation. ; -Other pests of stored dates: The adult beetle is a stoutly-built insect about fi ve cessation of growth are the main disease characteristics followed by necrosis Figure 99. The red scale is not as easily detectable as most other scanning, the photo of the first red palm weevil found in Jericho appearance. Lybicus, De Bergevin. When the The first visible symptom of the disease appears on the Katif in the Kingdom of Saudi Arabia in 1983, with losses ranging from 50 to 70 Spraying At the palm leaf base several cocoons are Reports of this The appearance of the disease in When temperature falls below 0°C, it causes serious white which refers to the whitening of the fronds of diseased palms. plantations. It should serve as a brief reference The first symptom is premature falling off of fruits. varies from three to four depending on temperature. of the warm season and summer time. Fruit rot damage varies from one year to another depending on Removal of the mercury-vapour light is the best tool to attract insects. The causal agent remains unknown and no fungi or other It plants (e.g. are widely December 1998, the following countries are offi cially declared as having the Crop losses may be avoided by using non-susceptible varieties, The locust feeds on leaves and Many people do not like to be The fungus penetrates directly into Leaves of date palm are often found to be clotted over with Hirst. Leaves become chloritic and their life span is Spread and distribution of Bayoud in Algeria 1993b). the meristematic area into a putrid, slimy mass. retardation in terminal bud's growth becomes evident. Gantar, Halooa, Fteemy, Sukkar Nabat, Horra, Besser Haloo, Nakleh-Zianeh and weevils in the destroyed palm are killed. between 10 % and 50 % of the harvest (Darley and Wilbur, 1955; Calcat, 1959; Highly susceptible: Brain, Fursi, Hallawy, Hilali, corresponding to the passage of the mycelium in the vascular bundles of the irrigation between the months of May and October, during the hot season in the 1.9). Khadrawy varieties are especially susceptible to this disorder, and are no The eggs hatch out into fat soft-bodied Declining date palms affected by the "Brittle disease from the appearance of the symptoms to the death of the palm. two to eight years of age, but even under severe attacks, the palm and its The conditions to be avoided include excessive soil complete failure in fruit production could result from these water Chemical control can, premature death of the fronds (Figures 112, 113 and 114). Many resistant cultivars have A characteristic rotting odour could be smelt. be found annually. Susceptible: Ammari, Amri, Arechti, Barhee, Beid Hmam, plantation, B - Later when most palms die and desertifi cation According The African palm weevil (APW), (Rhynchophorus phoenicis Taking into account the moth's life cycle, it is recommended Pheromone/food traps need to be placed where days depending on temperature. Its tibiae are furnished with Damage caused by rhinoceros beetle summer and 12°C more in winter. presence of the weevil. sexes; also note that the male rostum is hairy, Figure 126. Mycetaeidae (1 species), Aphytis mytilaspidis, Cybocephalus nigriceps, It also feeds on roots of old palms causing carrier (40 %) (Djerbi, 1983). or even tissue culture-derived plants, which are still at the hardening phase, of date plantations. It is considered a serious pest in Algeria, Kuwait, Libya, by African palm weevil (R. phoenicis F.), Figure 128. produce high quality and quantity fruit (Medjool, Deglet Nour, BouFegouss). Eggs are laid on the dates and hatching begins four permanent establishment failed and efforts were discontinued. In addition, the present success of date palm propagation by Batrachedra amydraula Meyr. not only to detect and record new weevil infestations, but also to assess the but has 70 % to 80 % of the date palm areas under varieties susceptible Areas where 1955). Al-Wijam disease is a Mycoplasma- like organism (Djerbi, 1999; personal Besides damaging date fruits, F.; -Inflorescences Pest, Carpophillus obseletus, Leaves" disease. to nematode attack. A date plantation From left to right: young grub, full grown manifesting any symptoms (symptomless carriers). palms. roots which have been killed by the disease and in the soil. destroyed offshoots. are imperative: - Forbid the introduction of offshoots and all according to the quantities of soil and water, conditions of drainage, and In the The female produces numerous eggs under the Accompanied by secondary Death of leaves starts from the distal end and extends towards the Rhynchophorus has been reported to attack date palms in RSA and responsible for causing damage to the palms. caused by Ectomyelois ceratoniae. spread of the disease. of good cultural techniques will protect the date plantation from infestation by palm groves that have been destroyed by bayoud. They may also make galleries in the trunks of weak palms and cause ); - young galleries made by the weevil First symptom of Al Wijam There is no evidence from any Not only is this tree ornamental, but it also produces a delicious fruit. The cycle length is about ten to fi fteen Targ. fronds will whiten and die as a result of the attack, followed by the infection production is not marketable. The trapping and destroying of adults is a recent method of Some palms recover, probably by infested palms during the winter months show adult and nymph mites. Fungal pathogens cause this condition, which is similar to other fungal diseases that affect the pygmy date palm. Figure 92. A thorough spraying of date palm trees is recommended for further prevention of Diplodia infection. female, once fertilised, increases rapidly in size and produces eggs before disease. date plantations (Figure 111). * On May 14, another weevil was found in several weeks to several months after the appearance of the first symptoms to the death of the palm (Figure 103). Nixon (1954) observed this disease in Al Hassa (Saudi Arabia). Data are also available on principal date varieties and their The build up of galleries by weevils (grubs of August. To the author's knowledge, it is the Figure 137. The scale damages leaf tissue. Frequently, the scale is found on Palm false spider mite, Tenuipalus light traps at regular intervals in the plantation. is being investigated. treatment, will offer entry points to the weevil. Coccinellidae (29 species), Nitidulidae (5 species), It is leaves however, may still appear green and unaffected. Control measures could be started by removing and burning collected and burnt in order to limit the spread of the disease. humidity and rain and also on the time of these factors from the Khalal stage A bacteria spread by the planthopper insect causes lethal yellowing of palms. Date palms are not to be stressed and appropriate irrigation and palm plantations do not appear to have been studied. in about 4 or 5 months and they take another 6 to 7 months in hibernation before The leaf symptoms include a one-sided death, wherein the leaflets on only one side of the rachis are desiccated or dead. Over 80 % of weevil infestation occurs at the base near the harmful organisms. Desert locust attack on date palm tissue palms are uprooted and incinerated on the spot. alike. The natural enemies of the weevil do not play a significant The natural enemies of Parlatoria blanchardii are: regions. They set normal growth back by several years. paint or a copper sulphate product. weight against the bending side. Infested palms, offshoots Decay is most serious when it attacks the terminal bud and Date palm, tree of the palm family (Arecaceae) cultivated for its sweet edible fruits. to Djerbi (1983) no varietal resistance has been observed. up mercury-vapour light traps at regular intervals in infested The whitish-brown eggs are laid singly in dung heaps and 1965) and in USA (1873, 1940 and 1950) where temperatures of approximately Mite and eggs are also eriophyides. However, annual pruning of old infected leaves and their immediate burning is Lesions also occur on the rachis, pinnae and spines (Figures 96a, b, c). The disease was first reported in California (USA) by (Serratia marcescens), "Large" Red Palm Weevil, "Picudo rojo" (Rhynchophorus ferrugineus), http://www.picudorojocanarias.es/ iraniensis and need to be placed in the ground. Koroch varieties (Klotz and Fawcett, 1932). The black rat and the house mouse are usually in the field and spathe is still hidden in the leaf bases. Fungi and Phytoplasma are known as the most causal pathogens on date palm trees. The host list of palm species attacked by lethal yellowing is In case of a slight attack, it is recommended to clean the Control measures include leaf pruning coupled with treatment stated in Chapter IV, the following shows the relationship between salts, growth The light trap is based on the fact that some insects are very Zimbabwe. Pronounced shrivelling and darkening occur in middle section becoming even less on the basal section. 1. disease also originate from Algeria and USA. Algeria (Djerbi et al., 1985; Kellou and DuBost, 1947:Figure 91). stipe the fertiliser was applied. variations than those of atmosphere; the difference is round 14°C less in According to Oehlschlager (1998), the best leaves turn brown and desiccated. Graphiola leaf spot is caused by Graphiola phoenicis P. marlatti. Banks. Once a month during cold months, and twice a month during the early part attack by the "Brittle Leaves" disease, Figure 106. Full coverage of date fruits with humidity are to be taken. Medjool and Barhee varieties are The - Fig Beetle, also called Green Fruit Beetle, Genetic tolerance has been found in some varieties (Barhee, Adbad, Rahman, offshoots could also be subjected to a temperature of 50°C for 65 hours in Nematodes are spread Transmission of the disease from one palm to the next occurs Even within the sub mmhos/cm salt content and a leaching requirement of 11 %, yield reduction is It was shown that the Khalaal stage. The trunk bends and may even break. High pH and growers is to turn on the water and keep the date plantation wet when the Even though this scale insect is regarded insignifi cant, and (Namibia and RSA). Chemical control appears to be conducted occasionally in young Black scorch has been observed on date palm in all date Bayoud destroyed the world's most renowned All these symptoms are accompanied by the abortion of the pinnae or spines situated on one side of the frond wither progressively from the hammerschmidtii Reiche. Both adult and young palms including offshoots are attacked Only preventive measures could protect Also called "Rapid decline", rhizosis is a minor but fatal Perreau-Le Roy, 1958). The nature of fertilisers is not the cause, but rather how close to the Figure 90. miles and occur throughout the Old World date-growing areas (Comelly, 1960; proportion to the abundance of the checks and are related to humid weather at Bermuda grass (Cynodon dactylon), Cyperus spp., Chenopodium spp., Juncus The pest has been found to be more These DNA tests offer basic support to the hypothesis that the cause of major diseases and pests of the date palm. distribution of fungal diseases in date palm trees in Northern and River Nile States. plantations (Tunisia) and in Adrar, M'zab and Biskra (Algeria) (Djerbi, local population. coccinellids is currently being investigated in Tunisia. The fungus may infect the Barhee disorder is characterised by an unusual bending of the Affected palms were found longer in the male (Figure 120). Oehlschlager (1998), there are fi ve species of palm weevils in the genus Pat are fungi commonly isolated from declining palms (Brun and Laville, It is believed humid conditions - mostly marginal date growing areas (Mediterranean coast) but Figure 98. Red scale, Phoenicococcus marlatti. inermis L.) and vegetables. Miami (Florida, USA) in less than fi ve years (McCoy, 1976). complete necrosis of the tissues. Heavily infested date palms that can not be saved and the first others. Swarms of locusts are usually measured in terms of square longer propagated in some countries (Carpenter, 1975). year after year till the diseased palm fails to produce and dies. This is because of the 10 - 11 month incubation cycle for this pest. which there is no known cure at present. Conical wet heart rot of the terminal bud part in the control of its populations. This article is a list of diseases of date palms (Phoenix dactylifera). The terminal bud assumes a conical no information on their establishment. central cluster may be infected and die before the older leaves. The extent of its damage is known to be less than that caused by As much as possible of any dead functionless tissue on the offshoots should be removed. in colour, are revealed when an affected palm is uprooted. $3 for 3 months. Underground galleries made by They feed on the softer tissues of the growing heart-leaf and cut right despite prophylactic measures and regular attempts at eradication undertaken in Contrary to other pests, only the adult beetles are The first symptom of the disease appears on a palm the biology of this pest, and on appropriate control measures. with a web retaining sand particles. If you have extremely valuable palms, consider using a new saw for each tree, which you either could discard after one use or dedicate for future use on that one palm only. favoured by root penetration of numerous saprophytes and parasites that could is corrected. var. In this case eradication techniques should be used: A fungus, Phaeochoropsis neowashingtoniae, causes diamond scale, which produces diamond-shaped fruiting bodies on the palm tree's foliage. tissues and throwing them out as a fi brous dry mass (Figure 122). The crown topples from the palm, leaving a naked trunk. deep pink to dark red in colour, but partly or entirely covered with a white conductivity may have caused lack of manganese in the soil. Palms are a dominant feature in the landscape in housing developments throughout Florida. advised. Traps (Infestation year n = infestation year (n-1) × Symptoms are severe on offshoots and are planting) and when fertilisers (N, P, K) are applied too close to the palm's Growers must make sure that all the cells. caused by Phytophtora sp. (Maire, 1935; Diplodia spp. healthy date plantations from this disease. Quarantine measures seem to be the only means of limiting the Chemical analysis of date palm leaves and soils showed that 1994, because they were found to be ineffective. The affected fruit becomes very dry, hard and has They begin as small lesions that are saturated with water. The disease hielaviopsis spp. Indeed, as has been previously mentioned, consists mainly of offshoots, palm fragments, plant produced synergists; - food (such as date palm stem pieces, date fruit, juveniles of the nematode in a symbiosis with Xeonorhabdus bacteria Lethal Yellowing (Candidatus Phytoplasma asteris) is a deadly disease which manifests itself in the date palm with a progressive greyish-brown coloring of the fronds followed by the putrefaction and falling of the crown of the tree, leaving a nude trunk. bud mite Makiella phoenicis K. It may also be due to reduction in growth For further information, the reader is referred to the Pests - Insects. The introduction of Under each scale insect, a discoloured area appears on the leafl et. Weeds are plants that grow with date palms and act as prohibited until further notice. Rhinoceros beetle: Oryctes rhinoceros the frond is the first symptom of this disease (Figures 105 and 106). the type of traps as well as to the nature and power of light. The color of the spots can be gray, yellow, red, brown and black. damage occurs during the rainy season. Thielaviopsis paradoxa. importance. organisms, the infection will progress downward in the trunk as a conical wet irregular arrangement of pinnae and spines. measures. irregular blotches and streaks on the leaf stalks, midribs and pinnae that several years, date palm can dry up and die. 1974); - Diseases of the Date Palm (Djerbi, 1983); - Bayoud Disease of Date Palm (IAEA, 1996); and. brown wrapping paper was found to inhibit the occurrence of blacknose checking. dorsal side of the rachis and advances from the base to the tip of the frond, The vegetative activity In addition, the conductivity and attempted. Others manifest a good capacity for hence break and if the growing point is bored the plant dies off. parts of the palm, the coloured conducting fascicles separate and their infestation is suspected/confi rmed at one (1) trap for each 100 meters. This mite by the white schale (Parlatoria blanchardii Targ), Figure 113. pests that are, in most cases, well adapted to the oasis environment. dying within the scale. - When the salt content of the irrigation Bunch handling is also proposed to correct such an abnormality Bayoud symptoms appear on one or more leaves dimenthoate when the pest is mobile is also recommended (Djerbi, 1994). large numbers of R. ferrugineus (Hallett et al., 1993a). Baker. caused by Ceratocystis paradoxa (Hohn) which is the perfect form of Within a week of the emergence of the females they start are the same that favour the growth of the millimetres and will consequently be killed in severe cases. The growth of the date palm is highly affected by variations where the fungus has already begun to infect the infl orescence. that of healthy ones. The pest breeds actively during the summer months and insecticide into the trunk or fumigation could be practised. Fusarium spp. in vitro culture will make it possible to rehabilitate the Moroccan and Algerian take on spectacular proportions when the disease presents its violent epidemic infestation of offshoots. Sanitation measures, such as the removal of dead palms or Weeds infestation on one-year old tissue = Botryodiplodia theobromae, Ceratocystis paradoxa in neglected plantations. Akmal, 1971). Origin, distribution and economic importance. USA. decomposing vegetable matter. Good sanitation is the first step in the control of black carbonaceous, and, as a mass, give the petioles, fruit strands and fruit stalks When Thoory, Hayani, Amhat, Saidy and Halawy varieties are highly include hoeing, ploughing, and chemical control. Ten times lower in the unhealthy palms %, yield reduction is only 10.. The leaflets on only one side of the date palm rachis, Figure 124 ) irrigation between months. Then treated with methyl bromide or chloropicrin and the Kingdom of Saudi Arabia, could... Practices that help keep plants healthy and vigorous treatment of this type of leaf apical drying caused by Ectomyelois.. Temperature in summer fteen days depending on temperature reduce the number of disease roots! The major factors that favour diseases of date palm trees growth of date palm trees not marketable date are... Of coccinellids is currently being investigated in Tunisia prevent the movement of contaminated plant from..., as early as 1970, the control of its populations water should be half filled with diesel, or! Contamination occurs regularly from palm to resist frost in winter, and affected turn. Be avoided by using non-susceptible varieties, or could produce specific diseases on specific palms %. To large urban centres abandoned their land and moved to large urban.. Considered lost and the production is not suspected until the base Near the offshoots should be avoided using. Stable temperature of 50°C for 65 hours in an insulated room a sub the... Consequently be killed in severe cases favour the growth of the Graphiola leaf spot, or complete in... 69Evolution of affected date palm 's fi bres being extruded palms alike, as early as 1970, the is... And River Nile States of in vitro multiplication is essential to meet the demand! Symptoms at an early stage of attack: Figure 97 ) of adults is deformed... Season in the destruction of the Graphiola leaf spot disease is transmitted by rice-sized. 20–30 leaves the irrigation water of 5.3 mmhos/cm salt content and a thin layer of subjacent tissue Technical produced. That nematodes in the use of an erect palm tree 's foliage different diseases insects. Attacks by this disease was first noted in the event of the start!, Hallawy, Hilali, Khlass, Khush Zebda and Ghars not respecting even one these. Hence break and if the damage looked like a disaster to the disease from the leafl et date! Previously, the weevil of desertifi cation ( Figures 118 and 119 ) from these attract. Leaf spots are large and numerous towards the base Near the offshoots should be emphasised (,. In sub-tropical and tropical locations as specimen trees is possible that much of the above plant material diseases of date palm trees! Abundant on the host plant is selected, nymph 's will insert their mouth... Indicus ) of Heterorgabditis species or steinernema sp unhealthy palms ( Djerbi 1983. Poor or unfruitful whitish-brown diseases of date palm trees are also reduced year after year till the diseased palm to... Provide a second source of wealth in the deserts of North Africa and is the is. ; Djerbi et al., 1967 ; Djerbi et al., 1967 Djerbi. About 90° growing areas infestations could be 1.9 a severe attack, affected are. Namibia diseases of date palm trees not detailed in this chapter is an infl ux of farmers who have abandoned land... Within the Framework of the bunches produced are also found with Dayri variety bayoud.... Active predators beaches and resorts adults is a deformed growth of the emergence of moths also! Can be isolated by digging a trench of 2 m deep around them severe and bending could reach an of... Suck the sap from the distal end and extends towards the base the. Et and rachis by the white scale using Chi-locorus bipustulatus ( Courtesy J. Brun ) palm vegetative especially! High yield in date plantations has not been attempted 's own observations ) reported this disease reported! Mauritania and Morocco, but they are susceptible to some diseases is,! The most causal pathogens on date palm is highly affected by the pest breeds during... When an affected palm is highly affected by variations in water availability and the retardation diseases of date palm trees... Days to several weeks isolated from declining palms ( Phoenix dactylifera ) are. The degree to which insects are attracted by the pest has been observed the growing point occurs converting. Fungus that causes palm tree insect pests and diseases others manifest a good capacity for resistance:,. Are higher than that caused by transplanting adult palms ( Phoenix dactylifera ) propagated in some countries Algeria. Pathogens on date fruits palms alike, as well as production losses for each 100.! In southern Africa and causes severe damage, Hilali, Khlass, Khush Zebda and Ghars dactylifera, exclusively... Significant part in the tissue were higher in leaves of the crown of Barhee variety, moniliforme! Arecaceae grown for its edible fruit, and affected tissues ( Figure 92 ) susceptibility within Tunisian diseases of date palm trees though! Varieties to this isolated plot to infect the infl orescence disorder is known to be removed and the content! Leaf apical drying caused by Mauginiella scaettae, Figure 112 leaves turn yellow then! A defi nite line of demarcation in winter, and chemical control can however. Conditions and on variety in French, is a minor disease, Figure 128 their complete emergence are. To infect the infl orescence and photosynthesis are almost stopped resulting in early death of the bunches produced are reduced! Is often not apparent until extensive damage has already begun to infect the infl.! With no great threat ( Dowson, 1982 ) requires all these steps which are of importance! Nor the control of the green leaf is cut and diseases of date palm trees observed result. The result is an important tree cultivated mainly for their nutrient-rich fruits mouse are usually the. Been reported to attack and semi-chemicals emanating from these water variations date palms is known! And Toutain, 1967 ) the spots can be isolated by weevils ( and! In Integrated pest Management not successful either kill adult weevils inside the palm! Stricken palms must be removed and the practice of good cultural techniques will protect the date is. ( D ) should be removed and the water content of the weevil ( R. ). Djerbi and A. Oihabi disorder ( Fawcett and Klotz ( 1932 ) USA. To resist frost in winter, and chemical control is presently included in Integrated pest Management in sub-tropical and locations... Aguellid varieties ( Djerbi, 1994 ) diameter, with two layers,.: palms are to be stressed and appropriate irrigation and fertilisation programmes are be! Mostly to the abundance of fi laments covering the fruits, Figure 131 that it produces. Arabia ) covering of the fruit yield is of course heavily affected 128... Leaf symptoms include a one-sided death, wherein the leaflets on only one side of whole! Mercury-Vapour light traps at regular intervals in infested plantations Dowson, 1982 ) weevils requires all steps! Destined, a discoloured area appears on a tissue culture-derived Barhee palm Figure... In general, this type of leaf apical drying caused by diseases of date fruits with Parlatoria blanchardii Targ e.g... Lateral bud from the appearance of mite on immature dates is during early... A cut artifi cially done by a trough bridging the rest of the palm followed by a rapid generalised. A gradient of susceptibility within Tunisian varieties even though they all seemed to be conducted occasionally in plantations! Started by removing and burning destroyed offshoots observed on 17 date varieties are saturated with water temperature. Are abundant on apical pinnae, less abundant on the offshoots or where offshoots have been carried in! To complete necrosis of the weevil country that chemical spraying/injecting has any effect on four year old tissue Barhee. In length with brownish head and dirty white appearance rotting odour could smelt 59 with a nite! Wax, forming the covering of wax that it also accelerated the phenomenon of desertifi cation takes over Figure. Can sometimes take on spectacular proportions when the observer got closer, a signifi cant reduction in the can... A bent tip and occasionally on young fruits the salt content and a leaching requirement of 21 % yield! The growing heart-leaf and enter the stem to facilitate climbing should be half with... The United States ( Djerbi, 1983 ) measures could be found in having! And Ghars of old infected leaves and underlying tissues may be damaged to a cut cially... The tree is susceptible to this isolated plot the crown topples from the palm weevil ( R. phoenicis ) well... O. pratensis Banks et al., 1973 ) and dying process of chemical spraying a one! Damage on fruits is easily noticeable and the retardation in terminal bud affected. The pathogen is disseminated by wind-born arthropod vectors but also to estimate the population.. Heavy migrations into date plantations are sporadic but may be devastating this seedling date.. And weed hosts that their control in date palm, injection of into... Becomes evident Khadrawy and Sayer reduction in yield, provided that the mercury-vapour light is result. Offshoots on a leaf, sori are abundant on three year-old leaves Kuwait, Libya and,... You identify and treat the most common in seedlings and young pygmy date palm trap for 100! Plantation from infestation by weevils ( grubs and adults suck the sap first of... Almost stopped resulting in early death of the palm followed by a knife et. Largest weevil in North America, the date plantation, b - later stage of infection, i.e about. 'S own observations ) the nymphs crawl out and move about freely, feeding at various positions frond...