Pests In Egypt Research Articles

Plant essential oils for the management of two serious stored pests in Egypt

The potential of four essential oils (Lavender, Catnip, Geranium, and chamomile) was evaluated against larvae and adults of confused flour beetle and red flour beetle under laboratory and store conditions. Geranium oil gave the highest cumulating mortality percentage 75.3% and 87.9% after 7 days of treatment in the state of T. castaneum and T. confusum, respectively. Geranium oil exhibited the highest repellent activity followed by Lavender oil. The ovipositional repellent efficiency of oils on foams and coverage gunny sacks displayed several methods of action by decreasing the egg numbers, which nearly repressed the progeny emergence percentages and high malformation percentages of tested insects. The oviposition was inclusively inhibited. The treated foam with Geranium or Lavender oils and covering gunny bags provided effective protection of the stored wheat.

Productivity, pathogenicity, host range, and spore mass-propagation of local strain of Mattesia sp. isolated from insect cadavers of certain stored grain pests in Egypt

Average yields of Mattesia spores (spore productivity) had varied from a minimum yield (0.17 × 107 spores) for Laemophloeus turcicus adult to a maximum yield (7.46 × 107 spores) for Plodia interpunctella larva. Comparatively, the highest increase in Mattesia spore yield, recorded from P. interpunctella larva (7.46 × 107 spores) over the lowest one, estimated for L. turcicus adult (0.17 × 107 spores), was nearly 44-fold. The increase in Mattesia spore yields that calculated from the other hosts (P. interpunctella pupa or moth; Galleria mellonella larva; Rhyzopertha dominica adult; Sitophilus zeamais), over that estimated for L. turcicus adult, was less than 10-fold (6–9-fold). Based on the weight of 1 g of the insect host infected with Mattesia sp., small stored grain insect hosts (e.g. L. turcicus, S. zeamais, and R. dominica) seemed to achieve Mattesia spore yields more than the larger ones (e.g. P. interpunctella). The increase in spore yields over that used for the inoculum, based on an average of 25 P. interpunctella larvae per bioassay container, was ca. 2 to 31-fold. These results revealed that the Indianmeal moth, P. interpunctella, could serve as a potential host for mass propagating the isolated entomopathogenic protozoan, Mattesia sp. Besides Mattesia larval mortality, survivors of Mattesia infection suffered deformities and noticeable undersized pupae or adults than the control ones. Also, many copulated moths (ca.46%) were unable to become separated after copulation until they had died. Bioassay of siftings, obtained from L. turcicus-protozoan-infected stock cultures, was carried out in order to emphasize the suppressive potent role of such protozoan entomopathogens in long-term storage. With the highest tested concentration of the studied siftings (10%), mortality responses due to Mattesia infection ranged from 13 to 68% at 14–169 days post-treatment. The corresponding figures for Adelina infection were 7–42%.

Interaction of Spinosad and Bacillus thuringiensis on Certain Toxicological, Biochemical and Molecular Aspects in the Egyptian Cotton Leaf Worm, Spodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae)

The cotton leaf worm, Spodoptera littoralis, is one of the most injurious agricultural pests in Egypt. In the present study, the interaction between spinosad and Bacillus thuringiensis, using different pairings, in third and fifth instar larvae was determined. Activities of α- and β-non-specific esterases and acetylcholinesterase (AChE) were also determined. Additionally, AChE transcript abundance using the real-time polymerase chain reaction (PCR) was detected. The cumulative percentage mortality of S. littoralis, third and fifth instar larvae, to spinosad and B. thuringiensis were increased gradually by increasing the concentrations. Spinosad was more potent than B. thuringiensis. Sequential application of these bio-insecticides, on the LC25 level on third and fifth instar larvae, when spinosad was first applied, showed synergistic interaction and additive effect, respectively. On the other hand, when B. thuringiensis was first applied, using the same timing of application, additive interaction was observed for both third and fifth instars. Individual, simultaneous and sequential applications of these bio-insecticides induced variable changes in α- and β-esterases and AChE activities. Real-time PCR (qRT-PCR) revealed an increase in transcript abundance up to 2.0-fold in third instar larvae in case of sequential and simultaneous applications. Based on the results herein, integrated pest management programme using spinosad and B. thuringiensis can be successfully developed for the control of S. littoralis.

Efficacy of some promising plant essential oils to control the red palm weevil Rhynchophorus ferrugineus olivier (coleoptera: curculionidae) under laboratory conditions

Red Palm Weevil is the most dangerous palm pest in Egypt and the Middle East. This study was conducted to evaluate some plants essential oils for use in the control of this pest in egg and larval stages. five individual different oils (orange oil, lemon oil , eucalyptus oil , castor oil, and basil oil)and three mixtures of (chilli+ thyme + lavender =)k1, mixture of (Colocynth and neem) = k2,and mixture of (Radicchio + turmeric +Silene ) = k3 with 5 concentrations of 1%, 3%, 5%, 7% and 9% for each one was used as aqueous solutions. Each concertation contains three replicates with ten eggs or larva for each replicate. The eggs were sprayed with different solutions while the larvae were fed on the sugar cane pieces after being dipped in the solutions for 20 seconds. The results of statistical analysis showed superiority the plant oils from orange and lemon showed remarkable mortality (p≤ 0.05) in the number of dead larvae and non-hatched eggs followed by eucalyptus, basil and Castor while other treatments recorded low number of mortalities of larvae and non-hatched eggs. The L.S. D values (2.49 ,6.19) for eggs and larvae respectively, showed that there were significant differences between oils and significant differences between concentrations. orange and lemon oil showed the strongest effect at 9% followed by the other concentrations, while k1 and k2 oil had no significant difference with the control at 1%. The study showed that orange and lemon oils as well as eucalyptus, basil and castor can be used in the control of this pest in the stage of the egg and larva.

Impact of nanosilver-profenofos on cotton leafworm, Spodoptera littoralis (Boisd.) larvae

BackgroundThe cotton leafworm, Spodoptera littoralis (Boisd.), is one of the most dangerous pests in Egypt and Africa, causing significant economic loss of cotton crop yield. The frequent use of insecticides to control this insect has led to the development of a generation’s resistance to them. The need of a new, safe control method and effective insecticides has become necessary after the recent increases in environmental pollution and insect resistance. This study is devoted to developing a novel synthetic scheme to produce a pesticide nanocomposite of very high efficiency compared to the originals. The nature of its chemical binding has been investigated via Fourier transform-infrared (FT-IR) and transmission electron microscopy (TEM) techniques.ResultsIn this work, the method is based on using silver nanoparticles (AgNPS) as a pesticide carrier by loading the organophosphorus pesticide profenofos on to their surface. The profenofos, AgNPS alone and nanocomposite profenofos (AgNPS@P) have been tested against second- and fourth-instar larvae of laboratory and field cotton leafworm. Our findings indicate that the AgNPS@P is more effective on cotton leafworm larvae than each of profenofos and nanosilver alone. The activity of AgNPS@P (LC50 = 0.94 and 5.15 ppm) was increased to 85 and 69 times more than that of profenofos (LC50 = 79.52 and 356.97 ppm) against second- and fourth-instar larvae of field cotton leafworm.ConclusionsThis method may be successful for reducing environmental pollution and the resistance of this pest to many pesticides.

Physiological and molecular genetic studies on two elicitors for improving the tolerance of six Egyptian soybean cultivars to cotton leaf worm

Cotton leaf worm (Spodoptera littoralis) is considered one of the most destructive agricultural pests in Egypt. Six soybean cultivars (Giza-21, Giza-22, Giza-35, Giza-82, Giza-83 and Giza-111) were grown under natural infection with cotton leaf worm. The effect of two elicitors, methyl jasmonate and sodium nitroprusside on enhancing the ability of susceptible cultivars to tolerate (Spodoptera littoralis) was studied. Giza-35 and Giza-111 showed tolerance performance under natural infection compared to Giza-22 and Giza-82 as sensitive ones, while Giza-83 and Giza-21 showed moderate tolerance. Both treatments positively affected seed yield and its components and fatty acid composition. Extracted fatty acids showed variable changes in treated plants compared with the untreated controls. Plants treated with the two elicitors showed an increase in Linoleic acid and Linolenic acid fatty acids and decrease in Palmitic acid and Palmitolic acid content. Treatment with methyl jasmonate was found to be more effective than sodium nitroprusside and enhanced resistance of the susceptible cultivars. Eight IRAP and iPBS retrotransposon-based markers were used to detect genetic differences among studied soybean cultivars and to develop molecular genetic markers for cotton leaf worm infestation. The technique successfully identified soybean genotypes in addition to nineteen molecular markers related to soybean tolerance.

Two chromatographic methods for the quantitative determination of some pesticides applied for cucumber pests in Egypt

AbstractTwo novel sensitive and accurate thin‐layer chromatography and high‐performance liquid chromatography methods were used for monitoring the residues of four pesticides: mandipropamid, metalaxyl, thiophenate methyl and carbendazim, which are widely used to eliminate cucumber pests in Egypt. The first method is a thin‐layer chromatography method, using silica gel plates as a stationary phase and hexane/methanol/acetone/glacial acetic acid (7.5:2:0.5:0.1, v/v) as a developing system. The second method is high‐performance liquid chromatography using isocratic elution and a mobile phase consisting of acetonitrile/0.02 molar potassium dihydrogen phosphate buffer (25:75, v/v) at a flow rate of 1 mL min−1 with UV detection at 225 nm. All the obtained results were evaluated regarding the agricultural committee of Egypt and showed acceptable pesticides residues.

Back Cover: Two chromatographic methods for the quantitative determination of some pesticides applied for cucumber pests in Egypt

Sep. Sci. plus 2018, 1, 334–342 DOI: 10.1002/sscp.201800012 The cover picture shows two novel sensitive and accurate thin layer chromatography and HPLC methods that were used for monitoring the residues of four pesticides; mandipropamid, metalaxyl, thiophenate methyl and carbendazim, which are widely used to eliminate cucumber pests in Egypt; the first method is a HPTLC method, using silica gel plates as a stationary phase and hexane, methanol, acetone, and glacial acetic acid as a developing system; the second method is HPLC using isocratic elution and a mobile phase consisting of acetonitrile and potassium dihydrogen phosphate buffer with ultra violet detection. The proposed HPTLC and RP-HPLC methods are precise, accurate and validated analytical procedures. The advantage of the developed HPTLC method is that many samples can be run simultaneously using a small quantity of developing system, it shows a high selectivity in short analysis time. The suggested chromatographic methods can easily be used for quality analysis of cucumber to make sure the pesticides dose is within acceptable limit. Application of these methods to commercial formulations showed that excipients do not interfere with the determination of the studied pesticides and hence it can be used for their determination either in bulk powder or in commercial formulations.

Genetic Fingerprinting of Root Knot Nematode as important Pest in EGYPT

Root knot nematode is considered as one of the most important nematode all over the world in Egypt it was found out that theses nematode attack the root system of most vegetables, fruits and Feld crops causing significance damages and economic loss .Using the morphological characterization isn't enough for nematode identification to species. So different molecular technology was used to identify different isolated of these nematode for fast and more accurate results. The internal transcript spacer (ITS) and restriction fragment length polymorphism (RFLP) of Ribosomal DNA (rDNA) sequences were used to distinguish between different major species of root knot nematode. DNA fragments containing the internal transcribed spacer (ITS) rDNA were amplified from DNA genome of different Meloidogyne spp. isolates from different governorate in Egypt. Ten females were used to amplify PCR product. When primers 5368 and 5367 were used for amplification of the ITS region, every isolate from the Meloidogyne spp. gave one major product of approximately 760 bp. When ITS regions of all isolates were digested with restriction enzymes, by using RFLP test (Restriction fragment length polymorphisms), the size of the DNA fragment using Hind III was strong band at 560 bp and another weak band at 200 bp that is typical for M. incognita and M. javanica with Hinf I, bands of 440 and 320 pb were obtained while 520, 240 bp bands were cleared when EcoRl are used. Four bands of 220, 200, 180 and 160 bp were obtained when I restriction enzyme was used. In multiplex test, a fragment of 415 bp was obtained when M. incognita was used as template (positive control), that confirming the fact that most nematodes isolates in Egypt are M. incognita

First report of field bindweed (Convolvulus arvensis L.) penetrates the roots of pepper (Capsicum annuum L.) plants.

Bindweed (Convolvulus arvensis L) is a root competitor weed that represents a major constraint for several crops production all over the world. Bindweed has adopted a parasitic lifestyle on pepper plants (Capsicum annuum L) in Egypt. Parasitic plants develop a multicellular infectious organ called a haustorium. In March 2017, 42 samples were collected from Minia and Beni Suef governorates, Egypt and evaluated for their virulence against pepper plants. Pathogenicity test was carried out in Sids Research Station. These populations tested were able to attack the pepper roots (Balady variety) appearing polar and dwarf leaves compared to leaves of uninfected control plants. The histological studies of Convolvulus arvensis and pepper roots revealed that the vascular xylem of the bindweed primary and secondary haustoria eventually connected with phloem conducting elements of the host root. By using the light microscope, boundary features of the penetration site and connection of the secondary to the primary root (in healthy pepper plants) were compared histologically with those of the haustoria and the host root cells (in infected pepper plants). These findings are important in assessing the potential of the parasite as an agronomically significant pest in Egypt.

Age-related changes in the chemical composition of female pheromone gland of the Egyptian cotton leafworm, Spodoptera littoralis (Lepidoptera: Noctuidae)

The Egyptian cotton leafworm, Spodoptera littoralis (Lepidoptera: Noctuidae) is a serious pest that attacks a wide range of crops in Egypt. To relate the age with the chemical composition of the pheromone gland of the female S. littoralis, the chemical components of the gland were analyzed using gas chromatography coupled to mass spectrometry (GC-MS). The pheromone glands of the females were excised at four different ages: newly emerged (D0v), one-day-old (D1v), two-day-old (D2v), three-day-old (D3v) and three-day-old mated females (D3m). Altogether the pheromone glands contained 54 compounds in the hexane extract. The compounds identified were 1 ketone, 1 acetate, 2 fatty acids, 3 esters, 6 aldehydes, 12 alcohols and 29 hydrocarbons. Their presence and relative amounts in the gland varied with age. Few compounds were observed in the glands of D0v, increased in D1v, D2v, and D3v, and remained almost constant in D3m. Fifteen compounds were previously identified as sex pheromone components in other Lepidoptera; the major compounds were the two hydrocarbons, hentriacontane, and heptacosane. Another fifteen components were previously identified from different insect orders other than Lepidoptera. The other twenty-four compounds were identified for the first time in insects. Determination and identification the sex pheromones of S. littoralis may present safe biologically active compounds that could be used in the management programs for this pest in Egypt.

Evaluation of the synergistic effect of gamma irradiated Steinernema scapterisci and soil depth in controlling Bactrocera zonata Saunders (Diptera: Tephritidae)

The Peach fruit fly, Bactrocera zonata (Saunders) is a serious devastating pest in Egypt. This pest spends in soil from full grown larvae till adult emergence. Therefore, the present study was planned to evaluate the pathogenicity of Steinernema scapterisci against larvae and 1 day old pupae (at different soil depths), and to investigate the effect of gamma radiation on its virulence. The results revealed that adult emergence percentage decrease as the soil depth and S. scapterisci concentration increase. In contrast, the larval mortality increased with S. scapterisci concentration increased. In addition, this study showed that gamma irradiation of S. scapterisci juveniles with 2Gy increased its virulence against both larvae and pupae, which presented by lower LC50 values than unirradiated S. scapterisci. Subsequently, it could be concluded that 2Gy irradiated S. scapterisci can serve as a bio-tolerated control method for B. zonata.

Effectiveness of Three Bio-Rational Products and a Traditional Insecticide against <i>Thrips</i> spp. and <i>Bemisia tabaci</i> Attacking Tomato Fields in Kafr El-Sheik Governorate, Egypt

Destructive effects of conventional insecticides on environment have created a necessity to introduce bio-rational products in pest control programs. Effectiveness of bio-pesticide (Beauvaria bassiana), natural oil (anti-insect), a botanical extract (nimbecidine) and malathion insecticide was evaluated against Thrips spp. and Bemisia tabaci attacking tomato in Kafr El Sheik, Egypt. The trial was conducted during two successive seasons; 2017-18 in a total area of 4912 m2 cultivated with tomato cultivar zero 42. The experiment was set up in a randomized complete block design with five replications for each treatment. Yellow sticky traps were used to monitor population of both pests before and after spraying, in addition, their numbers on plants were counted. Results revealed that highest control rates of both pests were recorded after the fourth day of each spraying. Long inter-applications periods decreased effectiveness and the greatest control resulted when three consecutive sprayings were applied. Malathion achieved the highest suppression of both pests. Within the bio-rational pesticides, nimbecidine gave the greatest thrips control whereas products showed no significant difference for whiteflies. The study recommends those bio-rational compounds to join Integrated Pest Management programs of both pests in Egypt, taking into consideration spraying for 3 consecutive times with at least 5 days intervals.

Mortality and nematode production in Spodoptera littoralis larvae in relation to dual infection with Steinernema riobrave, Heterorhabditis bacteriophora, and Beauveria bassiana, and the host plant

The present study aimed to evaluate the interactive applications of the promising biocontrol agents, the entomopathogenic nematodes (EPNs) Steinernema riobrave and Heterorhabditis bacteriophora and the entomopathogenic fungus (EPF) Beauveria bassiana, each at the LC25 level, to the last instars of the Egyptian cotton leafworm, Spodoptera littoralis, in either sequential or simultaneous fashion to determine whether interactions (synergistic, additive, or antagonistic) among these entomopathogens were present. Moreover, the indirect impact of two cultivated host plants (cabbage and cowpea) and three wild host plants (castor, Jew’s mallow, and mallow) or their primary metabolites (total protein, carbohydrate, and lipid content) on the virulence of these entomopathogens and on nematode production also was assessed. Synergisms were observed among the different entomopathogen pairings. In case where sequential applications were made, applying the EPF first was best for infective juvenile (IJ) production; applying the EPN prior the EPF significantly reduced IJ production. Larvae raised on cabbage (the most lipid–rich diet) were most resistant for both EPN species tested. In general, not many IJs were produced from hosts that fed on mallow, but many were produced from hosts that fed on castor. In the case of EPF, B. bassiana was most effective at controlling larvae that fed on mallow, which was considered the least nutritive of the host plants. The results obtained are suggestive of an efficient control to S. littoralis. This would be achieved through the implementation of an integrated program including combining the entomopathogens studied with each other, or intercropping castor (in the case of the nematode application), or mallow (in the case of the fungus application) with cotton for enhancing the control of this insect pest in Egypt.

ISOLATION, TOXICITY AND MOLECULAR CHARACTERIZATION OF NATIVE Bacillus thuringiensis ISOLATES FROM EGYPTIAN SOIL

Thirty three local soil samples were collected from Westward till Sewa Oasis in Egypt to search novel isolates of Bacillus thuringiensis (Bt) and evaluate their toxic potentiality to overcome the serious problem of evolved resistance by insects to the pesticidal activity. The first instars larvae of cotton leaf worm (Spodoptera littoralis) were used to test their toxic potentiality in the presence of the two standard strains kurstaki (K) and neoleonensis H24a (N). The results showed that three isolates from Alexandria (AL3, AL7 and AL11) and two isolates from Kafr - el-Dawar (KD2 and KD3) were presumptively confirmed as Bt. by morphological and microscopic characters. The treated larvae with Insecticidal crystal protein (ICP) exhibited mortality percentage around 50% for all isolates except AL3 isolate. The vegetative insecticidal proteins (VIPs) of KD3, KD2 and AL11 isolates revealed mortality percentages more than 75%. While, AL3 and AL7 isolates showed differential toxicity. Crystal proteins analysis by SDS-PAGE showed KD2, KD3 and AL11 isolates gave similar profiles as those of K strain which was characterized with 135 kDa and 70 kDa bands. AL3 isolate failed to show any noticeable bands. According to their plasmids patterns, 4 kb was shown in all isolates and the reference strains except AL3 isolate. Cry1, Vip1 and Vip2 genes of the isolates was detected by polymerase chain reaction (PCR). The results indicated that one band with 550bp in size was present in all isolates except the AL3 isolate. Vip1 primer succeeds to amplify a band 400 bp in size in all isolates and “K strain. Vip2 primer failed to react with any genome of the studied isolates or reference strains. This study suggested that KD2, KD3 and AL11 isolates may lead to be identified as potential strains of Bt. for their use in the development of bioinsecticide to control insect pests in Egypt.

Effect of several insecticides on pomegranate aphid, Aphis punicae (Passerini) (Homoptera: Aphididae) and its predators under field conditions

The pomegranate aphid, Aphis punicae (Passerini) (Homoptera: Aphididae) is one of the most important pests in Egypt on pomegranate trees. The study presented in this paper was conducted from 2012 to 2013 to compare the efficiency and selectivity of neonicotinoids (acetamiprid, imidacloprid, thiamethoxam and dinotefuran), organophosphate (malathion) and carbamate (pirimicarb) insecticides against pomegranate aphid and the associated predators, Coccinella undecimpunctata Linnaeus, Chrysoperla carnea (Stephens) and Syrphus corolla Fabricius. These insecticides significantly reduced the pomegranate aphid population by an average of between 70.6 and 90.7%. The effects persisted for up to 15 days after the end of treatment. The greatest control of A. punicae was achieved by thiamethoxam > acetamiprid > imidacloprid > pirimicarb > dinotefuran > malathion. Acetamiprid, imidacloprid, thiamethoxam, malathion and pirimicarb were harmful to predators and the observed reduction ranged from 75.4 to 100% and dinotefuran was moderately harmful to lacewings with an average reduction about 64.4%. These results suggested that the neonicotinoid insecticides can be considered as promising candidates for controlling the pomegranate aphid as, although they do have harmful to moderately harmful effects on predators, they are significantly less toxic to these beneficial organisms than malathion and pirimicarb.

Biological and molecular aspects of the insect growth regulator lufenuron on Spodoptera littoralis (Bosid) (Lepidoptera:Noctuidae)

Article History The cotton leafworm, S. littoralis, is a major pest in Egypt causes severe quantitative and qualitative losses of cotton and other economic crops. This study examined the effect of chitin synthesis inhibitors, lufenuron (match 5%) on the 2 nd instar larvae. The results showed that lufenuron caused not only mortality in larval stages, but also caused effect on pupal and adult duration, adult fecundity and egg fertility. Also lufenuron treatments have resulted in emergence of deformed pupae and adults. PCR-RFLP technique was used in this study to investigate the effect of lufenuron on the vira-like chitinase gene, one of the genes involved in the formation of chitin and concerned with development of insect. The endonucleases Spel, EcoRI and Bbsl were used to detect the molecular changes at different time intervals 6, 12, 24 and 48hrs post treatment with sublethal doses LC25, LC50 and LC90.The results showed significant changes in the sequences of the treated groups which were dose and time dependants. Moreover the number of RNA secondary structure stems was varied in the different studied groups and most of them differed in their nucleotide sequences, positions and free energy.

Evaluation of non-traditional approaches for controlling tomato moth, Tuta absoluta Meyrick (Lepidoptera, Gelechiidae), a new invasive pest in Egypt

Field studies were conducted in 2013 to determine the effectiveness of several treatments in controlling Tuta absoluta Meyrick and the impact of this control on the occurrence of other pests on tomato. The tested materials were microbial agent, Bacillus thuringiensis L., pure neem seed oil, fogging system and plastic mulches. The experiments were designed as randomised complete block with five replications per each treatment. Trials were evaluated on a two-week basis. Results obtained show that there is significant effect recorded between most of the treatments. Fogging system and tunnels are the best methods mainly because of the best overall performance on the tomato leaf miner.

Inducing Resistance in Olive Seedlings against Olive Psyllid, Euphyllura straminea Using Natural Phenol Compound

Olive psyllid Euphyllura straminea Loginova was recorded as a key pest in Egypt in 1988 on olive trees in El Arish and caused considerable losses in fruit yield. This work aims at evaluating the toxic and repellent effect of a natural phenol compound (3, 4 dihydroxy phenol ethanol) to control and induce resistance to olive seedlings against this insect pest under insectary conditions. Results showed that percentages of reduction of insect population were increased as the phenol compound concentrations increased. The reduction percentage of nymphs and adults were reached 100% after 15, 18, 21 days at concentration of 1.0, 0.75 and 0.5 mM, respectively. Also this compound was more effective on nymphal stage than adults. Spraying this natural phenol compound (3, 4 dihydroxy phenol ethanol) could be used to control and induce resistance to olive seedlings against this pest infestation. Also results indicated that increasing concentration of 3,4 – DHPE found to prolong the protective period from 17, 27 and 35 days at 0.50, 0.75 and 1.00 mM concentrations, respectively. Therefore this compound could be used to induce resistance of olive trees against olive psyllid infestation.

Scale insects (Coccoidae: Hemiptera) infested citrus trees and thier natural enemies, with a key of these pests in Egypt

Scale insects (Coccoidae: Hemiptera) are the most important pests infested citrus trees in Egypt. The present work dealt with the scale insects infested citrus trees and thier natural enemies as well as a key of these pests in Egypt . The results indicated that seven species of scale insects were recorded infested citrus trees in Egypt. Also taxonomic key of the seven species of scale insects was included. During the present work the results indicated that the populations of red scale, Aonidiella aurantii (Maskell) has two peaks one in April and the second one in October. In this work two parasitoids recorded associated with red scale. Theses are Aphytis lingnanensis Compere and Habrolepis aspidioti Compere and Annecke.It is recorded here two peaks for each parasitoid in April and October for A. lingnanensis and in July and November for H. aspidioti in Beni- Suef. Also this work indicated that citrus wax scale, Ceroplastes floridensis Comstock has two peaks the first in May and the second in October. In the present work two parasitoids recorded associated with citrus wax scale. These are Metaphycus helvolus (Compere) and Microterus flavus (Howard). It is recorded here two peaks for each parasitoid in May and October for in Gharbiya .The present work observed , black scale Chrysomphalus aonidum (L.) has two peaks the first in May and the second in November. In the present work two parasitoids recorded associted with the black scale. These are Aphytis chrysomphali (Mercet) and Encarsia citrina (Craw). It is recorded here two peaks for each parasitoid in May and November in Qalyubyia. The present work recorded seychellarum mealybug, Icerya seychellarum (Westwood) infested citurs trees in Demmyat and has two annual peaks one in June and the other in November. Also here Rodalia cardinalis Mulsant associated with seychellarum mealybug, I. seychellarum. During the presnt work the results indicated that he purple scale, Lepidosaphes beckii (Newman) has two peaks on citrus trees in Ismaillia . Also one parasitoid, Aphytis lepidosaphes Compere and one predator Chilocorus bipustulatus L. were recorded. During the present work the results indicated that parlatoria black scale, Parlatoria ziziphi (Lucas) has two peaks on citrus trees in Cairo. Two parasitoids, A. lingnanensis and E. citrina were recorded. During the presnt work the results indicated that citrus mealybug, Planococcus citri (Risso) has two peaks on citrus trees in Behira . Two parasitoids, Anagyrus pseudococci (Girault) and Leptomastix dactylopii Howard .