E. HASSAN: A review of Sorghum insect problems in Australia 151

Unterrichtung der F~inger ab. LAWROW (1957) versuchte in der Sowjetunion auf der Grundlage der Untersuchung der Felle auf den zentralen Lagern gewisse Schliisse auf die Fangintensit~it zu ziehen, hat aber keine fiir die Praxis auswertbare L6sung gefun- den. ERmNGTON (1963) versuchte aus extra-terrestrischen Ein- wirkungen (Sonnenfleeken-Zyklen) deren Einflut~ auf die Popu- lationsentwicklung der Bisamratte im Vergleich zu einigen anderen Nagern zu finden, aber auch dies brachte keine brauch- baren Ergebnisse. Vielleicht h~itte das PUSTETsche Material aus mehreren Jahrzehnten eine Mbglichkeit gegeben, die ERRING- roNschen Ergebnisse zu stfitzen oder zu widerlegen. Da sich solche extra-terrestrischen EinfliJsse aber auch auf Fauna, Flora und Klima u. a. erstrecken, w:,iren solche in die Untersuchungen einzubeziehen, dies diirfte aber den Rahmen obiger Betrachtun- gen welt ~bersteigen.

Schlie~lich sei noch die Einwirkung besonders nasser oder trockener Jahre auf die Arbeitsleistung der Bisamj/i- ger kurz gestreift. In Tab. 1 sind die Wasserst~inde der unteren Elbe nach dem Pegel Tangermiinde fiir einige Jahre angegeben. Bei 4,10m ufert die Elbe aus und /iberflutet die weiten Elbauen. Die besonders hohen Wasserst~inde in den Jahren 1955, 1956, 1957, 1958, 1961, 1965 und 1966 haben deutlich die Effektivit~it herabgedriickt, dagegen ergaben die trockenen Jahre wesentlich h6here. Zu berficksichtigen w~ire hierbei auch, in weleher Jahreszeit die Hochwasserwellen der Miindung zuflief~en und wie sich im weiten Hinterland die Nebengew~isser in trockenen und nassen Jahren aus- wirken. Aufzeichnungen sind hier~iber vorhanden und teilweise auch benutzt (HOFFMANN, 1967, 1970), viel- leicht kann hieriJber sp~iter berichtet werden.

Zusammenfassung Es wird eine auf einfachster Basis beruhende Methode ge-

schiidert, prozentual die Leistungen des offiziellen BekLmp- fungsdienstes zu errechnen. Die Problematik wird diskutiert. Es

wird u.a. ein Einfiuf~ der Wasserst~inde auf die Arbeitsleistung festgestellt.

Literaturverzeichnis BEC~CER, K., 1967: Populationsstudien an Bisarnratten, L AI-

tersanfbau. Zoologische Beitfiige (Berlin) NF 13 (2), 369----396.

ERRINCTON, P.L., 1962: Muskrat populations (Ames/Iowa). HOFFMANN, M., 1956: Die Verbreitung und Bek'~pfung der

Bisamratte in der DDR. Wasserwirtschaft-Wassertechnik (Berlin) 6 (1), 17--24; 6 (2), 60---62.

HOS~MANN, M., 1958: Die Bisamratte (Leipzig). HOI:FMaNN, M., 1967: Ein Beitrag zur Verbreitungsgeschichte

des Bibers im Grof~einzugsgebiet der Elbe. Hercynia (Leib- zig) NF 20 (4), 3---29.

HOFFMANN, M., 1970: Ein Beitrag fiber den Einflulg normaler und extrem kalter Winter auf die Best/inde der Bisamratte. Das Pelzgewerbe (Leipzig) NF 20, 4--18, 22--24.

HOFFMANN, M., 1974: Ein Beitrag zur Populationsdynamik der Bisamratte. Zeitschrift filr angewandte Zoologic (Berlin) 61, 385--394.

KN~CHTUL, CHR., 1980: Untersuchungen zur Populationsdyna- mik der Bisamratte in der DDR unter Beriicksichtigung der Reproduktion. Diplomarbeit Martin-Luther-Universitiit Halle-Wittenberg.

KNECHTEL, CHR.; PIEcHocKx, R., 1983: Zur Fortpflanzung, MortalitY/t, Sexilitgt und Alter der Bisamratte. Hercynia (Leipzig) NF 20, 259--278.

KNZCHTEL, CHR. ; SCHUH, J., 1984: Ein B eitrag zum circannua- len Rhythmus der Population der Bisamratte in der DDR. S/iugetierkdl. Informationen (Jena) 2 (8), 101--113.

LAXVROW, N.P., 1967: Die Ansiedlung der Bisamratte in der Sowjetunion (Moskau).

MEHL, S., 1956: Dr. phil. AUGUST PUST~T J'. Pflanzenschutz (Miinchen) 8, 85.

ULBRICH, J., 1930: Die Bisamratte (Dresden).

Anschrift des Verfassers: Agr.ing. MAx HO~X~AN~q, Loe- wenhardtdamm 17, D-1000 Berlin 42.

Anz. Sch~idlingskde., Pflanzenschutz, Umweltschutz 60, 151--155 (1987) �9 1987 Verlag Paul Parey, Berlin und Hamburg ISSN 0340---7330

Department of Plant Protection, Queensland AgricMtural College, Australia

A review of Sorghum insect problems in Australia

By E. HAss~q

With one Figure and 2 tables

Abstract The insect pests attacking grain sorghum in Australia are

reviewed. For easy handling the insects are grouped according to the stages in plant growth which they attack, e. g. pests of the planting and seedling stages, pests of the vegetative stage, pests of flowering stage and pests of the maturity stage. Reference is made to the importance of storage pests. The adoption of minimum tillage practices in Australian summer cropping areas, the importance of soil insects during establishment stage of the crop is expected to increase.

The sorghum midge Contarinia sorgbicola (Coquillet) no doubt is the most damaging pest species. Heliotbis armigera (Hiibner) is second in importance to sorghum midge as a pest of

sorghum. Damage and control methods of this and other pests are discussed. Economic injury levels are also discussed.

1 Introduct ion Grain sorghum Sorghum bicolor L. (Moench) is a

diverse species used for human consumption in some countries and as a feed for poultry and livestock in the form of grain, forage and fodder. Production of sorghum varies from small subsistence plots to immense monocul- tures. World production of sorghum grain for 1984 totalled approximately 73 t million produced on some 49.4 million ha averaging 1463 kg/ha (ANNo, 1985).

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152 E. Hxss~'~: A review of Sorghum insect problems i n Australia

Yields of individual countries of the world where sor- ghum is important varied from 3541 kg/ha in the USA to 171 kg/ha in Botswana. Table 2 shows the very wide range of yields produced at present.

Sorghum is mainly grown in the tropics and sub- tropics but is also cultivated to some extent in a few temperate areas. In Africa and Asia it ranks with maize and rice as a major food crop, and in the USA, South America and Australia it is grown as a grain crop as well as for forage silage.

Like most crops, sorghum is subject to attack by a large number of insects over 150 insect pest species from sowing to the final crop harvest and during storage (Jo'rwJ~ql et al., 1980).

Among the range of insects that can be found in sorghum crops, some are undoubtedly pests capable of inflicting, damage on the crop whilst others are predators or parasites.

Insects that are commonly regarded as pests of grain sorghum in Australia are summarized in table 1.

Of the insect pests which attack the crop the sorghum midge is economically the most important. Within Queensland it is estimated that control costs, residual losses and uncontrolled damage varies between $A5--10 miUion annually. Losses from other pests are very much less with Heliothis armigera (Hiibner) causing the bulk of such loss (PAssLow et al., 1984). Figure 1 shows insect attack at the different stages of the crop.

In this paper are discussed the various insect species which attack sorghum on the basis of the stage of crop growth involved: Planting and seedling stage, vegetative stage, flowering, maturity and storage.

2 Pests of the planting and seedling stages 2.1 False Wireworms

Larvae of these species attack the germinating seed and initial growth shoot and root. They cause sporadic

damage in a relatively small proportion of the sorghum producing areas. Experience has indicated that infesta- tions usually occur on the lighter soil types, and are noticably worse on land where stubble of the previous crop has been ploughed in. A weedy fallow usually favours their development because it enables the adults to congregate around and under the weeds, and lay their eggs. A pre-planting inspection is recommended to determine the populations. The current recommendation for control is to treat the seed with chlorpyrifos 250 W before planting (HAssAN, 1986).

2.2 Black Field Earwig This species creates some problems in the heavier

alluvial and red soils. The pest is a soil dweller, moving through the upper few centimetre of loose, cultivated soil. Observations indicate that this pest usually exists on organic matter such as decaying stubble. They attack planted seed, germinating seed and roots. Young plants that have suddenly wilted and died may be indications of black field earwig (HASS~'q, 1977). Limited data indicates that lindane at 1 g active/200 m row will give some con- trol (PAsszow et al., 1984).

2.3 Cutworms These species rarely cause widespread losses but isolat-

ed heavy infestations with consequent damage do occur. Larval feeding takes place mostly at night, the plants being cut off at or just below ground level. During the day time the cutworm larvae may be found lying in the soil or beneath debris within a few centimetre of the host plant (HAssxN, 1977). It is recommended to sample the area 5 days before and 5 days after sowing. Randomly sample 1--2 m2/ha, counting the larvae present in the upper 5 cm of the soil over each square metre samples (HAssAN, 1986). Suggested insecticides to be used include carbaryl, chlorpyrifos or trichtorphon.

)--Ants I -sarw~ I i--False Wireworm

]~Cutworm ~--Locust ~-Armyworm ~ltelJothla

~--Aphids

I

[--Thrips" [--Midge I ~Sorghum Head Caterpillar I

~-Yellow Peach Moth-~

seedling preboot boot stage flowering grain mitmity

Stage of Plant Development

Fig. 1. Usual occurrence of sorghum pests on various stages of plant development

E. HASSAN: A review of Sorghum insect problems in Australia 153

Table 1. Insects commonly regarded as pests of grain sorghum in Australia

Sorghum midge Heliothis Sorghumhead caterpillar Yellow peach moth Armyworms

Cutworms False wireworms

Ants Black field earwig Aphids

Migratory locust Australian plague locust Spurthroated locust Yellow winged locust

Contarinia sorghicola (Coq.) Heliothis spp. Cryptoblabes adoceta Turner Dichocrocis punctiferalis (Guenee) Mythimna convecta (Walker), Mythimna separata (Walker), Spodoptera exempta (Walker) Agrotis spp. Gonocephalurn carpentariae (Black- burn) Gonocephalum macleayi (Blackburn) Pterohelaeus alternatus Pascoe Pterohelaeus darlingensis Carter Pbeidole spp. Nala lividipes (Dufour) Rhopalosiphum maidis (Fitch) Rhopalosiphurn padi (L.) Locusta migratoria (L.) Chortoicetes terminifera (Walker) Austracris guttulosa (Walker) Gastrirnargus rnusicus (F.)

Table 2. Area, yield and production of the world's major sor- ghum producing countries (from FAO Production Yearbook 1985)

Countries Area Average Production 1000 ha Yield 1000t of in sorghum kg/ha sorghum

Nigeria 6 000 500 3 000 Botswana 35 171 6 Niger 850 235 200 Sudan 3 500 414 1450 Mexico 2 036 3 305 6 729 USA 6211 3 541 21994 Argentina 2 370 3 101 7 350 China 2 703 3157 8 532 India 16 500 715 11 800 Yemen A.R. 585 897 525 Australia 738 2 548 1 880

Aphid colonies are invariably attacked by a variety of insect predators and parasites. These are capable to brin- ging severe aphid populations back to negligible propor- tions in a few weeks, unless widespread spraying occurs for other pests of sorghum which affect the parasites and predators, If populations have not declined during head development excessive honeydew occurs on the heads and stickiness problems could be experienced at harvest. Other aphids also attack sorghum.

3.2 Heliothis Heliothis spp. damage may occur during vegetative

growth. The larvae feed mainly on the developing leaves in the growing tip. Damage at this stage, however, is not usually considered to be of importance. The species will be treated in greater detail in the maturity sectior~.

3.3 Armyworms Armyworms occurs commonly in grain sorghum and

from time to time there are severe outbreaks. The most important species are the day-feeding armyworm (S. ex- empta) and the northern armyworm (M. separata). Armyworms prefer to feed on succulent leaf tissue. While the armyworm plagues cause the most spectacular damage, scattered infestations are also capable of inflic- ting significant damage. These two types of infestation may be experienced in both young and advanced crops (SABIr~E, 1969). Armyworms in young crops, even in relatively small numbers, can cause serious reductions in the plant stand and spraying for their control is often necessary.

Present studies in Australia on armyworms concern only biological control. In the 1980's a consignment of the parasite Apanteles ruficrus (Haliday) was imported from New Zealand though it had been introduced from Pakistan. It was reported to have given excellent results (CuuBER et al., 1977, cited by PASSLOW et al., 1984). The same species are introduced to Western Australia and reports also indicate that establishment has been effected and that the species is having an effect on pest popula- tions (PAssLow et al., 1984).

2.4 Ants In some areas ants can seriously hinder the establish-

ment of a crop. The damage caused by ants is recogniz- able by gaps in the rows of seedling sorghum (TwxNE, 1972). The ants attack the grain as it swells prior to germination and eat out the germ material. Damage in a field is usually irregular but quite often the pest attack individual rows and prevent the germination. The pest is most commonly encountered in soils which have recently cleared scrub soils (SA~Ir~E, 1969). Where prob- lems are anticipated lindane at 300 g of 200 g/kg product per 100kg seed is applied as a seed dressing to minimise losses (PASSLOW et al./ 1984).

3 Pests of the vegetative stage 3.1 Corn Aphid

Aphids develop in colonies on individual leaves, in the throats of the sorghum plants or in the immature heads.

4 Pests of flowering stage 4.1 Sorghum Midge

The sorghum midge is one of the most destructive pest of grain sorghum in Asia, Africa, Australia, Europe and America. There are many other insects, diseases and disorders that may cause appreciable crop losses in sor- ghum locally, however, there seems to be no other single species with such widespread and important effects on sorghum yields (HARRIS, 1976).

The first report of this insect pest in Australia was made by Tyron in 1894 (PAssLoW, 1965).

The main economic effect of the sorghum midge is on sorghum grown for grain. Its damage is confined to the developing grain in the head. A severely damaged crop shows a large percentage of partially sterile heads.

The females mate soon after emergence and rarely live for more than 2 days, while the male lives'for a much shorter period. During this short time span she may lay up to 100 eggs. With the help of a long ovipositor these

154 E. HASSAN: A review of Sorghum insect problems in Australia

are laid into the developing florets before the yellow pollen is shed and during pollen shedding. The eggs hatch within a few days and feed on the developing grain, resulting in the production of partially sterile heads. The larvae pupate within the florets and the adults emerge at the end of pupal period, when tiny, white pupal cases are left attached to the glumes, Generally, there is a single larva inside each flower.

The midge survives from one sorghum season to the next as a fully developed larvae in diapause within the spikelets. To date Australian researchers have.not studied the triggering mechanisms which induce the species to develop diapause. Although the ability of the species to survive in diapause have been investigated. As shown elsewhere it has a remarkable ability to survive in this stage over a very wide range of conditions (PAssrow, 1965).

A clear relationship between rainfall, warm conditions and high humidity as the trigger mechanism for breaking diapause has been demonstrated. Planting to avoid flowering immediately after the major wet season as a method of midge escape has been employed over the years with some success. However, with the expansion of cropping into areas of irregular early to mid summer storms escape is not a reliable pest mitigation method (PAssLow et al., 1984).

PASSLOW (1958) recorded several parasitic wasps attacking sorghum midge. Nevertheless, the percentage parasitism of sorghum midge is low in the early and mid season crops and does not attain noticeable proportions until towards the end of the season.

Insecticide use gives a degree of control of the species. Thresholds for insecticide application have been set. In Australia, for the time being it is recommended that treatment is applied when there is one female per head. However, research has been undertaken in Australia in recent years to develop more objective economic injury levels for midge. Government research officers and pri- vate seed companies are also breeding for midge resistant hybrids. It appears that they are on the threshold of producing midge-resistant sorghum (PAssLow et al., 1984).

5 Pests of the maturity stage 5.1 Heliothis

Heliothis arrnigera is a major pest of a great variety of crops in Australia. It may attack sorghum at all stages up to the maturing of the grain. By feeding on the foliage, Heliothis larvae can give the plant a very ragged "shot hole" appearance. However, it is doubtful that this dam- age would seriously depress the yield. It is primarily a pest of the flowering head and developing grain. Larval feeding during the soft grain stages is the most serious and yield reductions can be expected. Attacks of this kind decrease as the grain approaches maturity. Webbing is not associated with damage. PAsszow et al. (1984) recommended crop monitoring within 4 days of 80 % of the crop having completed flowering. They consider that an accurate assessment of poulation can be obtained by Cutting samples of heads and spinning out the larvae into a bucket by twisting the stem between the palms.

A range of insecticides, such as synthetic pyrethroids, carbamates are recommended for larval control. TF~,KLE et al. (1983) showed that HeSothis nuclear polyhedrosis virus developed commercially gave good control of lar- ya e from 1st to 4th instar stages. Therefore, there is a good possibility for development of the virus as a control tool.

Heliotbis armigera developed resistance to pyrethroids in late 1982 and early 1983 after they had been used extensively on summer crops including cotton and sor- ghum itself. As a consequence, Government research workers, Plant Protection Departments of Education Institutions, primary producers and chemical companies agreed to a strategy for 1983--84 which restricted use of synthetic pyrethroids to not more than 3 applications on any one crop during the period of approx/mately 40 days from 10. 1. to 20.2. in most districts. It appears that the strategy is working.

5.2 Sorgburn Head Caterpillar Eggs are laid on the flowering heads through to almost

the harvesting stage. Hatching occurs after about 3 days and newly hatched larvae are yellow and about I mm long. Larval development takes about 2 weeks and a pupal stage one week. As they grow they feed continu- ously on the developing grain. The most severe damage usually occurs between the milky soft dough stage and harvest. Webbing is associated with larval feeding, which consumes portions of the grain and erodes grain surfaces, They are recorded widely through sorghum growing areas, however, they are more prevalent to the more humid coastal and tropical areas.

Insecticidal control is needed when damaging popula- tions of caterpillars occur, probably 10 or more per head. To achieve a good chemical control of the pest good penetration of the chemical in the closed head varieties is necessary. Therefore, in areas where problems are likely to develop open headed varieties are recommended to allow maximum penetration of pesticide. Chemicals used are endosulfan or trichlorphon.

5.3 Yellow Peach Moth This species is a pest of minor significance. It is more

prevalent in the wetter coastal and tropical sorghum areas than in inland production areas. They feed on the matur- ing grain and foul the heads with webbing and frass in a similar way to sorghum head caterpillar.

Control is needed when there are more than 5 larvae per head. Generally, insecticides used to control Hello- this or other larvae will control yellow peach moth also.

5.4 Locusts Of the numerous species of locusts which occur in

Australia, only 4 are considered to be pest in plague years and damage may be severe. They are not significant pests.

6 Pests of storage Most of the storage pests are associated with sorghum

grain. These pests can be controlled by protectants such as fenithrothion and carbaryl and fumigation with phos- phin when required.

A.H. EL-HENEIDY et al.: Survey of the parasitoids of the Greasy Cutworm 155

Zusammenfassung Eine /,.)bersicht der Schadinsekten yon Sorghum in Australien

Es wird eine Ubersicht der Insektenarten gegeben, die als wesentliche Sorghum-Sch~idlinge in Australien auftreten. Ihre Gliederung erfolgt nach den verschiedenen Wachstumsstadien des Sorghum. Auch die Sch/idlinge an Sorghum-Vorr~iten wer- den erwiihnt. Es ist zu erwarten, dai~ das immer geringer werdende Marl an Ackerbaumaflnahmen auf den australischen Sommergetreide-Feldern zur Erh6hung der Insektensch~iden ffihren wird.

Wichtigster Sorghum-Sch/idllng ist zur Zeit die Sorghum- Gallmficke, Contarinia sorgbicola (Coqu.), gefolgt vonder Noctuide Hetiotbis armigera (Hbn.). Die Sch/iden und Be- k/impfungsmethoden bei diesen und den anderen Schadinsek- tenarten werden er6rtert. Wirtschaftliche Schadensgrenzen wer- den betrachtet.

Literature Cited ANNO, 1985:1984 FAO Production Yearbook. Food and Agri-

cultural Organisation of the United Nations. Vol. 38 Rome. HARRIS, K.M., 1976: The sorghum midge. Annals of Applied

Biology. 84, 114--118. HASSAN, E., 1977: Major Insect and Mite Pests of Australian

Crops. Ento Press (Gatton), pp. 238. H^ss^N, E., 1986: Control of Insect and Mite Pests of Austra-

lian Crops. Ento Press (Gatton), pp. 476.

JoaxeAm, M.G.; YOUNG, W.R.; T~ETES, G.L., 1980: El- ements of integrated control of sorghum pests. FAO Plant Production and Protection paper, FAO, Rome 159 pp.

PASSLOW, T., 1958: Parasites of the sorghum midge Contarinia sorgbicola (Coq.) in Queensland. Queensland Journal of Agriculture and Animal Science 15, 35--36.

PASSLOXV, T., 1965: Bionomics of sorghum midge Contarinia sorgbicola (Coq.) in Queensland, with particular reference to diapause. Queensland Journal of Agriculture and Animal Science, 22, 149--167.

PASSLOW, T.; FRANZMAN, B.A.; ALLSOPP, P.G, 1984: Sor- ghum insect problems in Australia. Proceedings of the Inter- national Workshop on Sorghum Insect Pests. July 23--27, Texas A & M University and ICRISAT.

S~INE, B.N.E., 1969: Insect problems of grain sorghum pro- duction. Sorghum symposium (Emerald) QGGA, p. 51--57.

TE~,IiLZ, R.E.; PAGE, F.D.; SABINE, B.N.E.; GILES, J.E., 1983: Evaluation of Heliothis Nuclear Polyhedrosis Virus for Control of Heliotbis armigera on sorghum in Queensland, Australia. General Appl. Ent. 15, 11--18.

TwIN~, P., 1972: Insect control in sorghum. Summer crop seminar (Goondiwindi).

Author's address: Dr. E. HASSAN, Department of Plant Pro- tection, Queensland Agricultural College, Lawes (via Gatton), Queensland, Australia, 4343.

Anz. Sch~idlingskde., Pflanzenschutz, Umweltschutz 60, 155--157 (1987) �9 1987 Verlag Paul Parey, Berlin und Hamburg ISSN 0340--7330

Dept. of Biological Control, Plant Protection Res. Institute, Dokki, Giza, Egypt

Survey of the parasitoids of the Greasy Cutworm, Agrotis ipsilon Rott. (Lepidoptera, Noctuidae) in Egypt

By A. H. EL-HENEIDY and FAWZlA A, HASSANEIN

With one figure

Abstract Weekly samples of the cutworm, Agrotis ipsilon gott. larvae

were collected for 3 successive seasons 1983/84---1985/86 from 3 Governorates in middle Egypt to survey alad evaluate the role of parasitoids in suppressing the pest population.

Two gregarious internal larval parasitoids were recorded, Apanteles ruficrus Hal. and Meteorus rubens Nees. (Hymen- optera, Braconidae). Percentages of parasitism were estimated. They reached 20.2, 22.2 and 24.7 % in seasons 1983/84, 1984/85 and 1985/86, respectively, with an average of 22.5 % (10.3 % A. ruficrus and 12.2 % M. rubens). The highest rates of parasit- ism were recorded in March and April.

1 Introduction Cutworms are economically an important group of

lepidopterous pests. In Egypt, they attack many field crops such as wheat, faba bean, Egyptian clover, maize, cotton and some vegetables, their damage is of frequent occurrence allover the country (ZAAzOU et al., 1974). Agrotis ipsilon Rott. is the most abundant species of cutworms in Egypt, while other species are less abundant and sometimes of rare occurrence.

Bis~tAFat (1932), WILLCOCKS and BAHGAT (1937), HAFEZ (1947) and EL-MINSHAWY (1971) recorded Apan- teles ruficrus Hal., Gonia capitata Deg., Microplitis sp., Eulimneria xantbostoma Gray. and Meteorus laeviven- tris Wsm. as parasitoid species on A. ipsilon in Egypt. Meteorus rubens Nees. was recently recorded by the authors on A. ipsilon larvae, for the first time in Egypt (EL-HEINmmC and HASSANEIN, in press). The same species was found on A. ipsilon by KIM et al. (1982) in South Korea and by FOSTER and RU~SlNK (1984) in USA.

The present study was designed to survey and evaluate the role of parasitoids in suppressing the pest population in middle Egypt.

2 Methods and Technique Weekly samples of A. ipsilon larvae were collected all over the

active season of the pest (October--May) from different infested fields of faba bean, Egyptian clover as well as vegetable crops mainly in Fayoum and Beni-Suef and partly in Giza Governorates (middle Egypt) during the three successive sea- sons 1983/84, 1984/85 and 1985/86. The larvae were placed individually in glass vials (to avoid cannibalism), fed on fresh

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