A.M. AL-BELTAGY; S.S. ELTABAKH*; MA. MOURAD**; M.S. SHAWIR*** AND G.M. MOAWAD
Plant Prot. Res. Institute, A.R.C., Dokki, Giza , Egypt
* Fac. Agric., Alexandria . University , Egypt
** Cent. Agric. Pest. Lab., A.R.C., Dokki, Giza , Egypt .
‘‘ Fac. Agric., Alexandria . University , Egypt

Key Words: Bollworms, Insecticides, Pheromone, Yield properties.

PRELIMINARY EVALUATION OF PHEROMONE RELEASE IN RELATION TO PINK BOLLWORM INFESTATION IN COTTON FIELDS

A.M. Al-BELTAGY, M.S. SHAWIR*, M.A. MOURAD** AND G.M. MOA WAD
Plant Prot. Res. Institute, A.R.C., Dokki, Giza , Egypt
* Fac. Agric., Alexandria University
** Cent. Agric. Pest. Lab., A.R.C., Dokki, Giza , Egypt

ABSTRACT

Rates and duration of release of PB-Rope pheromone [(ZZ/ZE)-7, 1 1-hexadecadienyl acetate] were evaluated under field conditions. The rate of release was 0.71% from the active ingredient per day in the first three weeks. Thereafter it increased in the following seven weeks to about 0.80% a.i./day, while declined in the last four weeks to 0.65% a.i./day. The effective release period was about 70 days whenever approximately 50% of the a.i. was released. Accordingly, the daily rate of release became insufficient to disrupt pink bollworm population. The highest infestation percent in the pheromone treated area was 2.03% at the end of the effective pheromone period.

Key Words: Pheromone, bollworms, cotton fields.

PREDACEOUS MITES POPULATIONS IN RELATION TO CITRUS PESTS IN EGYPT

M.A. RAKHA AND M.E. EL-NAGGAR
Plant Prot. Res. Institute, A.R.C., Dokki, Giza , Egypt .

ABSTRACT

The relationship between predaceous mites and citrus pests was studied in three different localities in Egypt ; Qualyobia ( Nile Valley ), Beheira (Coastal area) and EI-Tahreer province (new reclaimed lands). The phytoseiid mite species Euseius scutalis (Athias- Henriot) was the most commonly encountered predator associated with phytophagous mites and whiteflies, while the predatory cheyletid mite Cheletogenes ornatus Canestrini & Fanzago was the most abundant species associated with scale insects.

Key Words: Citrus, Acari, Biocontrol.

M.F.S. TAWFIK, AMAL I. AFIFI, M.S.I. El-DAKROURY* AND F.M.H. EID*
Laboratory of Biological Control, Fac. Agric., Cairo University, Giza, Egypt
*Plant Prot Res. Institute, Dokki, Giza , Egypt

ABSTRACT

Chelonus sp. was first reported in Egypt in 1991 (Taw et al, 1992), attacking eggs of Earias insulana (Boisd.). The various stages of its life cycle (egg - four larva instars - prepupae - pupa and adult stage) were described. They differ in general dimensions.
Duration of various developmental stages, emergence and oviposition processes together with the egg laying activity were reported.

Key Words: Chelonus sp. Spiny Bollworm , Egypt .

H.A. TAHA R.A. SEDRAK, SAFIA T. ABDALLA* AND A.E. SHARAF*
Plant Prot. Res. Institute, Dokki, Giza , Egypt
* Field Crops Res. Inst., ARC, Giza , Egypt .

ABSTRACT

Field and laboratory studies were carried out to evaluate the relative susceptibility of 23 locally developed soybean genotypes to spider mite (Tetranychus urticae Koch) infestation. The obtained results showed that: 1) The genotypes F9H2 families 4, 20 and 29 were highly susceptible, 2) The genotype F9H2 family 21 was susceptible, 3) The genotypes F9H2 family 111, F7H family 31, F7H5 families 2, 15 and 19, F7H15 family 2 and M7 family 94 were moderately infested, 4) The resistant genotypes were: F7H5 families 9, 16, 22 and 23, F7H15 families 5 and 17, and F9H2 family 16, 5) The highly resistant genotypes were: F7H15 families 1, 10, 12 and 21 and F9H2 family 19.
Biological studies on the 23 genotypes showed that T. urticae females oviposition period and fecundity increased when they fed on susceptible genotypes.

Key Words: Spider mites, Soybean, Resistance.

A. M. KORAYEM AND SUSAN A. HASABO
Plant Pathology Department, National Research Center , Dokki, Cairo , Egypt

ABSTRACT

Activity of Helicotylenchus dihystera, Meloidogym incognita, Rolylenchulus renformis and Tylenchulus semipenetrans exposed to standard solution from bulb extract of both Allium cepa and A. sativum, shoot extract of Chenopodium album, C. ambrosloides and Seneclo aegyptius was reduced by 100% after 14 hrs exposure. Also, a 100% reduction in activity of all tested nematode species was obtained by 1:1 dilution from shoot extract of C. ambrosioides after 24 hrs exposure. A complete reduction in the tested nematode activity was not obtained at any exposure period and any concentration from Melia azedarach extract.
Activity of nematodes exposed to the standard concentration of shoot extracts from C. album, C. ambrosioides and S. aegyptius was not recovered when nematodes were transferred to water for 48 hrs. Activity of tested nematodes exposed to 1:1 dilutions of all tested extracts recovered by approximately 100% when nematodes were transferred to water. A complete inhibition in hatching (100%) was obtained with the standard solution from all tested plant extracts except of seed extract of M azedarach.

Key Words: Plant extracts, Plant-parasitic nematodes.

THE USE OF ANTIBIOTICS TO IMPROVE LABORATORY REARING CONDITIONS OF CULEX PIPIENS L. (DIPTERA: CULICIDAE)

A.N. HASSAN
Dept. Biological and Natural Sciences, Institute of Environmental Studies and Research,
Am Shams University

ABSTRACT

Heavy larval mortality, asynchronous development and decreased pupation rates were observed during laboratory maintenance of Culex pipiens L., the main vector of filariasis in Egypt . Three commercially available antibiotics, i.e. amblosin, erythrocin and tetracid, were added to rearing water and tested. Both axnblosin and erythrocin (0.5 mg/mI) were capable of improving the rearing conditions as indicated by synchronous larval and pupal development and decreased generation time. Pupation rate increased from 57% to 90-94% following the addition of the antibiotics. On the contrary, tetracid killed all Cx. pipiens larvae even at concentrations as low as 0.06 mg/mI.
It is suggested to use amblosin or erythrocin in the laboratory maintenance of Cx. pipiens to control possible microbial infections and to enable researchers to obtain large numbers of adults of similar age which are essential for laboratory studies.

Key Words: Antibiotics, Culex pipiens, Diptra: Culicidae.

A.M. AL-BELTAGY, A.M. SALEM *, MA. ELHAMAKY** R. ABU-AIANA AND M.E. OMAR*
Plant Prot. Res. Station, Alexandria
* Sakha Res. Station, Kafr El-Sheikh , Egypt
** Plant Prot. Res. Institute, Dokki, Giza , Egypt

ABSTRACT

Certain recommended insecticides and pink bollworm pheromone were applied in two locations (Abaadia and Elsafasif at Al- Behira Governorate) against pink boliworm. The side effect of these treatments was studied on same piercing sucking insects (aphid Aphis gossypii (Glov.), jassid Empoasca lybica (Deberg.) and whitefly Bemisia tabaci (Genn.), in 1991 cotton season. The three insects had different time appearance to population peaks (aphid on Aug. 19, jassid on July 30 and whitefly on Sept. 3, 1991). There was a significant difference between aphid population density under untreated area and both the pheromone and insecticide areas. There was no significant differences between the three insects population under pheromone and insecticide treated areas.

Key Words: Aphid, Jassid, Whitefly, Pink Bollworm Pheromone.

IMPACT OF CHEMICAL AND BIOINSECTICIDES AND THEIR COMBINATIONS ON ENTOMOPHAGOUS INSECTS IN COTTON FIELDS AND DAMAGE BY THE COTTON LEAFWORM AND BOLLWORMS

F.F. SHALABY, E.F. ELKHAYAT*, A.A. HAFEZ AND E.A. KARES*
Plant Protection Dept., Fac. Agric. Moshtohor, Zagazig University , Moshtohor , Egypt
* Plant Protection Res. Institute, A R C, Giza , Egypt

ABSTRACT

Thirteen predaceous and six parasitoid adult species were counted and the damage caused by the cotton Leafworm and bollworms was estimated throughout 1992 cotton season in untreated cotton plots and those received three applications of the recommended chemical insecticides, Delfin (a bacterial insecticide of Bacillus thuringiensis var. Kurstaki) and their combinations. Chemical insecticides showed drastic effect on predator and parasitoid adult numbers (overall average of 37.5 and 65.6% reduction, respectively), Baythroid had the severest effect, followed by Cutabron and Empire. Adults of Scymnus sp. suffered the severest effect due to chemical insecticide applications.
Although the bioinsecticides Delfin had the least effect on entomophagous insect numbers, the heaviest damage due to S. littoralis and boliworms infestation was recorded. On the other hand, the three applications of the chemical and bio-insecticide combinations had less harmful effect on relative populations of beneficial insects than using the chemical insecticides alone, and gave satisfactory reduction in the damage caused by the mentioned pests. Consequently, the chemical and bio- insecticide combinations were recommended to control target pests to restore the entomophagous insects and obtain better insect pest control.

Key Words: Bioinsecticides, Entomophagous insects, cotton leafworm, bollworms.

M.H. BELAL AND SAMIA M. EL-KABBANY
Department of Economic Entomology and Pesticides
Fac. Agric., Cairo University, Cairo, Egypt

Key Words: Artemisia monosperma, Insect Pests.

K.S. AHMED
Dept. of Biological and Geological Sciences,
Faculty of Education, Am Shams University , Cairo , Egypt

ABSTRACT

Rhabdepyris zeae was maintained in the laboratory on the second and third larval instar of Tribolium confrsum. At 25±2°C, the incubation period of the parasitoid egg was 3. days, the following larval instars lasted 10.2 1±1.3 days (3 instars), 3.7±0.09 days as a prepupa, and 13.76±1.34 days asapupa. Only one egg was deposited on each host larva. Sex- ratio in R. zeae was found to be 1.87:1 (female:male) in nature and that was close to that in the laboratory (1.8 1:1). The daily and total rate of egg deposited per female were 2.34±0.17 and 52.3±3.41, respectively at 25±20C. The mean longevity of adult female and male fed on hone last 28.16 and 25.32 days, while the starved adults lied for 2.2 and 1.82 days, respectively, at the same temperature. Percentage of parasitism reached its maximum on T. confusum (90%) while the parasitoid failed to survive on both Oryzaephilus surnamensis and Lasioderma serricorne. In 1989, the parasitoid was highly distributed during summer months in Giza , Cairo , Minia and Dakahlya Governorates

Key Words: Parasitoid, R. zeae, Rhabdepyris, Biology, Morphology.

BEHAVIOURAL RELATIONS BETWEEN THE GREEN LACEWING, CHRYSOPERLA CARNEA STEPH. AND ITS PREYS: I. INFLUENCE OF PREVIOUS FEEDING CONDITIONS

S.A.EL ARNAOUTY AND A. FERRAN*
Laboratory of Biological Control, Fac. Agric., Cairo University (Egypt), Cairo, Egypt
* Laboratoire de Biologie de Invertébrés, 37 bd du Cap 06606, Antibes (France)

ABSTRACT

The predaceous larvae of Chrysoperla carnea (Steph.) reared on Myzus persicae (Suizer) or Ephestia kuehniella Zell. eggs, presented as significant preference as a first choice towards the wingless females of M persicae. The predator reared on E. kuehniella eggs, consumed more preys than that reared on M persicae. For the feeding sequences, the data analysis revealed that the most frequent feeding pattern is two successive (spacewide) prey consumption. The colony reared on M persicae exhibited a higher frequency than that reared on E. kuehniella of non successive prey consumption, whereas this latter colony presented a higher frequency of 3 to 4 successive prey consumption than the first one.

Key Words: Chrysoperla carnea, Feeding preferences, Behaviour, Feeding sequence, conditioning.

S.A.EL ARNAOUTY AND A. FERRAN*
Laboratory of Biological Control, Fac. Agric., Cairo University Cairo, Egypt
* Laboratoire de Biologie de Invertébrés, 37 bd du Cap 06606, Antibes , France

ABSTRACT

The third instar larvae of Chysoperla carnea, present two types of movements; extensive search (rapid, in straight line), and intensive search (slow, in sinuous line) which occurs after the ingestion of the first prey. For the determination of the searching efficiency, prey individuals (wingless females of Myzus persicae Sulz. and eggs of Ephestia kuehniella Zell.) were placed on the perimeter of four arenas of different diameters: 4, 7, 11 and 15 cm; 8 preys in each case. The predator larva was placed in the center. The predator was more efficient in finding its preys in the smaller arenas which represented higher prey densities. However, the predator was able to find out preys that were isolated. Prey- finding behavior seemed to be a non-random search, when preys were on arenas of 4 or 7 cm, and occasionally on 11 or 15 cm- diameter. In the smallest arena, the predator, located in the center, usually started extensive search until finding the first prey, then turned to an intensive search behavior. In such a case, the predator consumed 6.0±1.6 preys on the average. However, in 3% of the cases the predator larvae consumed all the 8 available preys. On the other hand, only 0.8±0.9 preys were attacked in the widest arena.

Key Words: Chysoperla carnea, Random/non-random search, Behavior, Predator-prey interaction.

H.M. HASSAN AND A.A. ABD-EL ALIM
Plant Protection Dept., Fac. of Agric., Minia Univ.

ABSTRACT

Last instar larvae and newly formed pupae of Sesamia cretica Led. and Chilo agamemnon Bles. were exposed to Steinernema carpocapsae (All strain) and Heterorhabditis bacteriophora (NC strain). Larvae and pupae of C. agamemnon were susceptible to S. carpocapsae than H. bacteriophora. In contrast, S. cretica showed susceptibility to H. bacteriophora than S. carpocapsae. It is obvious that larval stage was more susceptible to infection than pupal stage. On the other hand, production of dauer larvae indicated the infectivity of nema todes which differ according to the host and the nematode species, whereas the production of S. carpocapsae from S. cretica was massive than H. bacteriophora. However, the emergence of H. bacteriophora was greater than S. carpocapsae from C. agamemnon larvae. It is obvious also that the production of nematodes from S. cretica in general was higher than from C. agamemnon. Histological examination of the infected larvae of S. cretica indicated reduction in contents of fat bodies, deterioration of muscles and body epithelial cells.

Key Words: Sugarcane borers, Entomogenous nematode, Sesamia cretica.

H.A. BORAEI
Department of Economic Entomology, Kafr El-Sheikh, Fac. Agric., Tanta Univ. , Kafr El-Sheikh , Egypt

ABSTRACT

The egg parasitoid Anaphes fuscipennis Hal. is recorded for the first time in Egypt on eggs of the Egyptian alfalfa weevil. The parasitoid was reread under the laboratory conditions; 18, 22 and 80C constant and 1 6/220C fluctuated temperatures. Results indicated that the parasitoid completed its life cycle within 17 days at the room temperature (19±3oC), however, the longest oviposition period (13.7 days), the highest fecundity (82.3 eggs/female) and the longest longevity (15.3 and 10.0 days for females and males, respectively) were recorded for the parasitoid reared under the lowest temperature (18°C). Sex ratio calculated from field samples was 2.5:1 female to male. Five generations of this parasitoid were reared in the laboratory.
Field samples were collected from January 20 to May 5. Peak of parasitism (52.6% and 48.3%) were recorded on April 4 and March 20 in the first and second seasons, respectively. Yearly means of parasitism were 12.8 and 15.7%, respectively.

Key Words: Anaphes fuscipennis, biology, egg parasitoid, Hypera brunneipennis.

ISOLATION OF BEAUVERIA BASSIANA (BALS.) FROM THE EGYPTIAN ALFALFA WEEVIL, HYPERA BRUNNEIPENNIS (BOHEMAN) AND ITS HABITAT IN EGYPT

R. EL-SUFTY, H.A. BORAEI AND Sh. ELGREMI*
Dept. of Economic Entomology
* Dept. of Agricultural Botany (Microbiology)
Fac. Agric., Kafr El-Sheikh, Tanta Univ., Kafr El-Sheikh, Egypt

ABSTRACT

Densities of the entomogenous fungus, Beauveria bassiana (Bals.) from soil under clover (Trifolium alexandrinum L.), eucalyptus tree-bark, clover plants and field population of Hypera brunneipennis (Boheman) adults were determined using a dilution-plate method. Samples were collected in three different localities at Kafr El-Sheikh Governorate in 1993. Viable B. bassiana conidia existed in up to 47.5% of the soil samples and reached an average of 1119.4±35 1.22 conidia/g dry soil and in 67.7% of eucalyptus tree-bark samples and averaged 2357±736.7 comdia/100 cm2. Lower densities were found on 12.1-21.8% of clover plant samples and in 25.9-43.8% of H. brunneipennis adults collected from clover fields.

Key Words: Beauveria bassiana, Hypera brunneipennis, Trifolium alexandrinum, Soil, Eucalyptus tree-bark.

AMAL. I. AFIFI, K.T. AWADALLAH, IMAN I. El-SEBAEY* AND M.F.S. TAWFIK
Biological Control Lab., Dept. of Econ. Entomology and Pesticides, Fac. Agric., Cairo University , Giza , Egypt
* Plant Protection Res. Inst., Agric. Res. Center , Giza , Egypt.

ABSTRACT

Coranus angulatus Stal., inhibits the host plant, Aihagi mouroum Med. At constant hygrothermal conditions of 30±1°C and 70% R.H., the male passed its nymphal stage through four instars, while the female passes this stage through five instars. Thus, the insect male passed the immature feeding stage in shorter period (42.4 days) than female (46.1 days). An average of 96±5.9 eggs per female was reported at a rate of 2 egg/female/day. The various stages of its life cycle (egg + five nymphal stages) were described. Measurements of head, antennal segments, rostrum, pronotum and body were considered. Mating and oviposition processes together with the egg laying activity were reported.

Key Words: Biology, Description, Coranus angulatus.

H.A. BORAEI
Department of Economic Entomology
Kafr El-Sheikh, Fac. Agric., Tanta Univ., Kafr El-Sheikh, Egypt

ABSTRACT

It is the first record of Mircoctonus sp. on the Egyptian alfalfa weevil, (Hypera brunneipennis Boh.) in Egypt . It was recorded from 11 localities at 4 governorates in the Nile Delta during the study which extended six years. Rearing, as a method for evaluating the percentage of parasitism, revealed that it ranged from nil to 30% with an overall mean of 8.0%. When the dissection method was followed, the percentage of parasitism ranged from nil to 12.5%with an overall mean of 4.7%. Higher levels of parasitism were observed when larvae were dissected during years of 1992 and 1993, since percentages of parasitism were 20 and 44%, respectively, with an overall mean of 40%.

Key Words: Microctonus sp., Hymenoptera, Braconidae, Alfalfa weevil.

USING CHRYSOPERLA CARNEA (STEPHENS) (NEUROPTERA: CRRYSOPIDAE) AGAINST THE GREEN PEACH APHID MYZUS PERSICAE (SULZER) IN GREEN HOUSES

S.A. El ARNAOUTY, E. FRANCO* AND M.F.S. TAWFIK
Biological Control Research Laboratory, Fac. Agric., Cairo University, Cairo, Egypt
* N.RA., 37 Bd du Cap 06606 Antibes, France

ABSTRACT

Second instar larvae of Chrysoperla carnea were released on green peppers in a green-house in order to control an aphid population of Myzus persicae. Over a study period of nearly 16 weeks, successful control was obtained in the treated green-house as the aphid population was maintained below the economic threshold (around 20 aphids/plant), however, in the control greenhouse where no larvae were released the aphid population underwent its exponential growth to reach 2384.5±380.5 aphids/plant, most of the control plants were with less foliage, flowerless and fruitless.

Key Words: Chrysoperla carnea, release, Green-houses, Green pepper.

FAWZIA A. HASSANEIN, A. SHOUKRY*; A. A. SARHAN* AND M. A. EWAIS
Plant Prot. Res. Institute, Dokki, Giza , Egypt
* Fac. of Agric., Suez Canal Univ. , Ismailia , Egypt

ABSTRACT

Opius nitidulator (Nees) is an internal parasitoid of Pygomia mixta (Villeneuva). It attacks the full grown larvae of the host before pupation. The biology of this parasite was carried out at various thermal conditions and all biological processes were described.

Key Words: Pegomia mixta, Opius nitidulator, Biology.

H.A.BORAEI
Dept. of Economic Entomology
Kafr El-Sheikh, Fac. Agric., Tanta Univ. , Kafr El-Sheikh, Egypt

ABSTRACT

The development of ovaries and testes of the Egyptian alfalfa weevil Hypera brunneipennis Boh. accompanied aging of the weevils. The longest ovaries (5.22 mm) and the largest testes (0.99 mm2) were detected in winter. However, gonads of parasitized weevils by Microctonus sp. which dissected in winter were still not significantly different from those aestivating weevils of summer. Histological studies revealed that germarium of reactivated winter females contained more developmental stages of oocytes and males contained more free spermatozoa and more dividing cells in comparison to aestivating ones.

Key Words: Egyptian alfalfa weevil, Sexual maturation, Aestivation, Microctonus sp.

POPULATION DYNAMICS OF THE MEALY PLUM APHID HYALOPTERUS PRUNI (GEOFF.) AND ITS ASSOCIATED PARASITOIDS ON PEACH

A.M.A. IBRAHIM AND AMAL.I.AFIFI
Biological Control Laboratory, Fac. Agric., Cairo Univ. , Cairo Egypt

ABSTRACT

In Egypt , Flyalopterus pruni (Geofftoy) is considered as a cosmopolitan pest of peach. The population dynamics of this aphid and its parasitoids, Aphidius colemani Vier. and A. picipes (Nees) on peach (Prunus persica) and reed plants (Arundo donax L.) was studied at Giza region, from December 1992 to November 1993. The aphid and its parasitoids existed allover the year on reed plants and only during nine months from February to October on peach trees. Two peaks of aphid infestation occurred on both hosts; the first during March, and the second during July on peach and August on reed plants. The maximum percentage of parasitism occurred in May (64.5%) and in September (48.8%) on peach and reed plants, respectively.

Key Words: Population dynamics, Hyalopterus pruni, Peach, Reed plants.

M.M. MATTER
Pest and Plant Protection Dept., National Research Center , Dokki, Cairo , Egypt .

ABSTRACT

Third instar Pieris rapae larvae were parasitized by the solitary parasitoid Hyposoter ebeninus before or after being subjected to Bacillus-treated cabbage leaves. Unparasitized larvae were treated as well. Results obtained, seven days after bacterial treatment, revealed that the LC50 value for parasitized larvae reached about 4.1 folds higher or 0.49 fold lower than that for unparasitized larvae when parasitism preceded or followed bacterial treatment respectively. Parasitoid progeny in hosts which have been treated after parasitism, were mainly depended on age of the parasitoid at the time of infection. Parasitization of previously treated larvae was detrimental to parasitoid production as it increased premature host death. Late third instar host larvae surviving low concentration of the pathogen and held for seven days were more responded to parasitism than similarly held nontreated hosts of the same age. Delay in development of sublethally infected hosts was advantageous for the parasitoid as it extended the exposure period of the preferable ovipositional instar. Nevertheless, fewer parasitoid females and malformed adults appeared among parasitoids emerged from treated medium. It was concluded that B. thuringiensis should be restricted or cautiously used when the parasitoid was efficiently acting in cabbage fields. However, it could be recommended at lower or moderate rates when the parasitoid was not able to control heavy infestations in the event that the late stages of the parasitoid are not affected by the bacterium and could retain its population again.

Key Words: P. rapae, H. ebninus, B. thuringiensis.

AMAL. I. AFIFI, A.M.A. IBRAHIM AND M.K. ELAKKAD*
Biological Control Lab., Dept. of Econ. Entomology and Pesticides, Fac. of Agric., Cairo University , Giza , Egypt
* Plant Prot. Res. Institute., Agric. Res. Center , Dokki , Egypt .

ABSTRACT

The hydrophilid Sphaeridium bipustulatum F. was collected from cow and chicken manures accumulated in the farm of Faculty of Agriculture, Cairo University . It was successfully reared in laboratory at 28*2°C and 70% R.H. on larvae of Musca domestica L. Under that hygrothermic condition, the total developmental period of this species averaged 49.0±0.9 days. Four larval mstars were reported for this species. The various stages of its life cycle (egg-four larval instar, prepupa, pupa and adult) were described. Mating and oviposition processes together with the egg laying activity were reported.

Key Words: Sphaeridium bipustulatum, Biology, Description.

A. M. A. IBRAHIM, S. A. EL-ARNAOUTY, K. T. AWADALLAH and M.D. ABDALLAH
Biological Control Laboratory, Fac. Agric., Cairo Univ., Cairo, Egypt

ABSTRACT

Chrysoperla carnea Steph. was reared in the laboratory to obtain a sufficient quantity of eggs for colonization. 95% and 90% of the released eggs hatched during the seasons of 1992 and 1993, respectively. In the first season, the predator/aphid ratio before colonization was 1:10.4 opposed to the ratio of 1:6.8 after colonization. In the second season, the corresponding figures were 1:8.4 and 1:5.5. Consequently, it appeared that the predator built up itself up and succeeded to decrease the aphid population. The percent of reduction in the two seasons reached to 51.8 and 16.6%.

Key Words: Chrysoperla carnea, Colonization, Aphids, Apple-tree

H. ABOU-BAKR, F.F. SHALABY*, M.M. ASSAR* AND M.F. FAHMY
Biological Control Research Laboratory, Fac. Agric, Cairo Univ., Cairo, Egypt
* Plant Protection Department, Fac. Agric., Benha Branch, Zagazig Univ., Banha, Egypt

ABSTRACT

On the basis of their pathogenicity to the 1st instar larvae of Spodoptera littoralis (Boisd.), 35 varieties of Bacillus thuringiensis (Berliner) were classified into 4 groups: a) 11 highly effective strains (caused >75% mortality); b) 5 moderately effective (50-75%); c) 9 weak (20-50%) and d) 10 ineffective (caused <20% mortality). B. thuringiensis toiworthi (HD-301) seemed to be the most effective strain tested, causing 100% mortality after 3 days. Two other strains of toiworthi (HD-537 and 125) caused 100% mortality after 5 days of exposure. Three strains, namely darmstadiensis, wushansis and aizawal (HD122) caused also 100% mortality, but after 7 days of treatment.
Toxicity values were estimated for each of the most 10 virulent strains, the least values were associated with the 3 totworthi strains confirming their pathogenic superiority. Spore counts/nil in the 10 tested strains indicated that the pathogenicity is rather attributed to the virulence of the spore-crystals than the number of spores.

Key Words: Bacillus thuringiensis, Spodoptera littoralis