5 04 H . S. Salama, F. N. Zaki and A . F. Sharaby

LAICO, F. M.; TAMASHIKO, M., 1967: Interactions between a microsporidian pathogen of the lawn-armyworm and the hyrnenopterous parasite Apanteles marginiventris. J. Invertebr. Pathol. 9, 546-554.

SALAMA, H. S., 1970: Rearing the corn bover Ostrinia nubilalis Hiibn. on a semiartificial diet. Z. ang. Ent. 61, 216-218.

WILLCOCKS, F. C., 1937: The insects and related pests of Egypt. I., Part 2, Insects and mites injurious to the cotton plant.

Address of the first named author: Prof Dr. H. S. SALAMA, National Research Centre, Laboratories of Pests and Plant Protection, Tahrir St. Dokki, Cairo, Egypt

Institute of Plant Protection, ARO, The Volcani Center, Bet Dagan, Israel

The toxicity of some novel pesticides - synthetic pyrethroids and benzoyl phenylurea chitin synthesis inhibitors - for eggs

of Spodoptera littoralis (Boisd.)’

By K. R. S . ASCHER, MIRIAM ELIYAHU, NADIA E. NEMNY and I. ISHAAYA

Abstract A series of pyrethroids was investigated as to their toxic effect against 0-1-day-old Spodoptera littoralis eggs and their LC5,’s were determined. Among the pyrethroids Decis was the most active compound, followed by Dowco 417 and Cymbush, and finally Pydrin and Ambush; Cybolt was found to be much less toxic. The benzoyl phenylurea chitin synthesis inhibitors Dimilin and PH 60-44 were more effective at 5 ppm than all the pyrethroids tested, except Deck and Cymbush. Decis was more toxic than Dimilin and PH 60-44 even at 1 ppm. Some further benzoyl phenylureas, such as P H 60-45, Dowco 439 and Dowco 401, had either only low activity or were inactive against S. littoralis eggs.

1 Introduction

In recent years there have been rapid advances in two groups of novel insect control agents, the photostable synthetic pyrethroids (ELLIOT 1977; ELLIOT et al. 1978; various authors, 1977, 1980) and the benzoyl phenylurea chitin synthesis inhibitors (GROSSCURT 1978; MAAS et al. 1980). The activity of the pyrethroids had been studied mostly against larvae, nymphs and adults, and that of the benzoyl phenylureas - against larvae and nymphs of insects. Much less work has been dedicated to the ovicidal properties of both groups of compounds. It was therefore deemed of interest to investigate their effect against eggs of Spodoptera littoralis (Boisd.), the Egyptian cotton leafworm, a serious crop pest in this country (AVIDOV and HARPAZ 1969) and the Middle East at large (TALHOUK 1969).

Contribution from the Agricultural Research Organization (ARO), The Volcani Center, Bet Dagan, Israel. No. 449-E, 1982 series.

US. Copyright Clearance Center Code Statement: 0044-2240/82/9405-0504 $ 02.50/0 Z. ang. Ent. 94 (19821,504-509 0 1982 Verlag Paul Parey, Hamburg und Berlin ISSN 0044-2240 I Intercode: ZANEAE

Toxicity of some novel pesticides for eggs of S. littoralis 505

2 Materials and methods

The test method was described in detail in previous work (ASCHER and MOSCOVITZ 1970; ASCHER et al. 1979) and consists essentially of dipping Spodopteru littoralis egg masses, which had been laid on filter paper and reduced to 100 counted eggs each, into aqueous dilutions of formulations of the test compounds; 0-1-day-old eggs were used and the tests were conducted at 27 "C. The synthetic pyrethroids tested were:

Ambush (permethrin) 25 % E.C., Makhteshim, Be'er Sheva. Cymbush (cypermethrin) 10 YO E.C., Makhteshim, Be'er Sheva. Titan - Ripcord (cypermethrin) 20 % E.C., Luxembourg-Palimport, Tel Aviv. Pydrin (fenvalerate) 30 % E.C., Luxembourg-Palimport, Tel Aviv. Dowco 41 7 - Vivithrin (cyano-[6-phenoxy-2-pyridinyl]-methy1-3-(2,2-dichloroetheny1)-2,2-

Becis - Decis (deltamethrin) 2.5 % E.C., Milchan Bros., Tel Aviv. dimethylcyclopropane-carboxylate) 40 % E.C., Luxembourg-Palimport, Tel Aviv.

The chitin synthesis inhibitors tested were all benzoyl henylureas, supplied in the form of wettable powders either by Philips Duphar, The Netherrands, or Luxembourg-Palimport, Tel Aviv (see figure for chemical structures):

OIFLUBENZURON "I

6 ' 1 1 - \ -C--NH-C-NH-Q-O-fH-Q e - - PH 60-45 CH3

The chemical structures of the four chitin synthesis inhibitors tested

Dimilin (PH 60-40; diflubenzuron) 25 % W.P. (PHILIPS-DUPHAR 1975). P H 60-43 [l-(2-chlorobenzyoyl)-3-(4-trifluoromethyl-phenyl)urea] 25 Yo

PH 60-44 ~l-f2,6-difluorobenzovl~-3-f4-trifluorometh~l-~henvl~ urea1 25 % W.P. (PHILIPS-DUPHAR 1979, 1980).

. - , , - W.P. (PH&S-DUPHAR 1976, i980a).

W.P. (PHILIPS-DUPHAR 1979). PH 60-45 [1-(2-chlorobenzoyl)-3-{4-(~-ethoxyphenyl)-phenyl}urea] 25 YO

It was of advantage that all the benzoyl phenylurea chitin synthesis inhibitors were supplied as wettable powders, since the average particle size in these formulations is < 5 Fm, which is an important factor in their activity (MULDER and GIJSWIJT 1973; PHILIPS-DUPHAR 1975; MAAS 1978).

3 Results and discussion

The results are expressed as percentage mortality obtained at different concen- trations of the pyrethroids (table 1) and of the benzoyl henylureas (table 2).

concentration lines and b (the slope of the lines) values are presented in the bottom of table 1. Both from the mortality data obtained at different concen-

For the synthetic pyrethroids, the LC,,'s obtained s rom the probit-log.

K. R. S. Ascher, Miriam Eliyahu, Nadia E. Nemny and I . Ishaaya

trations and the calculated LC50)s it seems that the py- rethroid most active against S. littoralis eggs was Decis, followed by Dowco 417 - Vivithrin, and Cymbush (cyperme- thrin); another formula- tion of cypermethrin, Ti- tan, was slightly less toxic than Cymbush. Pydrin and Ambush were both still less active. Another pyrethroid, AC-222, 705 - Cybolt [(RS)4-cyano-3-

phenoxybenzyl( S)-2-( 4- difluoromethoxypheny1)-

3-methylbutyrate] 30 % E.C., supplied by C.T.S., Petah Tiqwa, was found to be much less toxic to the eggs (at 50ppm a.i. only 45.1 f 16.8 Yo and at 10 ppm a.i. 17.7 f 4.5 %O

mortality were obtained). The ovicidal roperties

Dimilin (diflubenzuron) were discovered by ASCHER and NEMNY (1974). ABO-ELGHAR et al. (1976) found that there was a pronounced ovicidal effect when egg masses of S. littoralis were deposited on Dimilin residues on leaves; later this group re- ported that the material was very active in field ex- periments as an ovicide for the eggs of this insect on cotton (ABo-ELGHAR et al. 1980).

Assays of the ovicidal effects of liquid formula- tions of the benzoyl phenylureas suffer from inconsistent results (ASCHER and NEMNY 1974; ASCHER et al. 1980) due to different crystal

of the benzoyl p fl enylurea

Toxicity of some novel pesticides for eggs of S. littoralis 507

Tuble 2. The mortality of 0-1-day-old Spodoptera lzrrorulis eggs dipped in aqueous dilutions o€ the W. P.’s of benzoyl phenylureas (100 eggs in each replication; the number of replications is given in

parentheses; T = 27°C)

Corn p o u n d , Dirnilin PH 60-43 PPm (diflubenzuron)

Mean % kill zk S.E.

PH 60-44

100 50 25 10 5 2.5 1.25 1 0.75 0.5 0.35 0.25

97.2 f 1.6 (4) 94.5 f 4.1 (10) 99.3 f 0.6 (6)

100 (4) 100 (5)

52.1 f 9.6 a (12)

15.2 f 5.2 a (10)

0 (8)

’ 1.0 ?

100 (5) 100 (5) 100 (4) 100 (4) 100 (5)

99.5 f 0.3 (7)

76.5 f 10.0 (18) 42.7 f 10.6 (17) 44.3 f 12.3 a (14)

65.1 * 9.2 b (20) 38.2 f 6.0 (12)

0 (11)

73.6 f 5.8 b (23) 58.5 f 8.0 (16) 13.8 f 6.1 a (5)

4.3 k 3.4 (5)

- 0.75 4.9

? ?

Means in horizontal rows followed by different letters are significantly different at the 5 % level of probability.

sizes of the particles precipitating upon dilution (MULDER and GIJSWIJT 1973; PHILIPS-DUPHAR 1975; MAAS 1978), which can not be prevented completely by employing wettable powder formulations (see “Materials and methods”). According to the results obtained in the present study (table 2), PH 60-43 seems to be more toxic to Spodoptera littoralis eggs than is Dimilin or PH 60- 44 at a concentration of 1 pprn a.i., whereas PH 60-44 (also called, in the U.S.A., A13-63223 or penfluron) (OLIVER et al. 1977; PICKENS and DEMILO 1977; CHANG 1979) was more active than either Dimilin or PH 60-43 at 0.5 pprn a.i. These results are probably due to different slopes of the probit-log. concentration lines of these compounds. As in earlier work with Dimilin (ASCHER and NEMNY 1974; ASCHER et al. 1980), the results of tests at low concentrations of the benzoyl phenylureas were too variable to allow the construction of reliable probit-log. concentration lines. A conspicuous exam-

e of this is PH 60-44, which was more active (table 2) at 0.5 ppm than at two R! igher concentrations, 1 ppm and 1.25 ppm! These latter results are based on 14 to 20 hundred-egg replications for each concentration.

Although OLIVER et al. (1977) reported that PH 60-44 was superior to diflubenzuron as female sterilant against the boll weevil, Anthonomus grandis Boh., and CHANG (1979) found that it had a better (2 X ) sterilant action in the house fly, results by PICKENS and DEMILO (1977) indicated that it was not significantly better than diflubenzuron as an ovicide for the female of the face fly, Musca autumnalis de Geer.

PH 60-45 was much less active as S. littoralis ovicide: toxic (92.6 f 29.9 % mortality) at 100 ppm, inactive already at 50 ppm.

Two other benzoyl phenylureas tested were Dowco 439 (composition undisclosed), which was much less active than diflubenzuron, PH 60-43 and PH 60-44 (at 40 pprn a.i., kill was 96 % and at 30 ppm, only 21 YO); and

508 K . R . S . Ascher, Miriam Eliyahu, Nadia E. Nemny and I. Ishaaya

Dowco 401 [benzamide-2,6-dichloro-N- { 4-(2,2-dichloro-l ,I -difluoroethoxy- phenyl)amino}carbonyl], which was inactive at 100 ppm a.i.

If one compares the results in tables 1 and 2, it seems that at a concentration of 5 ppm a.i. the benzoyl phenylureas Dimilin and PH 60-44 were more effective as Spodopteru ovicides than were the pyrethroids, with the exception of Decis and Cymbush. At 1 ppm, Decis was still significantly more active than these two benzcyl phenylureas, but not PH 60-43.

Zusammenfassung

Die Giftigkeit einiger neuer Insektizide - synthetische Pyrethroide und Benzoyl-Phenylurea- Chitinsynthese-Hemmer - gegeniiber Eiern won Spodoptera littoralis (Boisd.)

Es wurden einige Pyrethroide und Chitinsynthese-Hemmer auf ihre toxische Wirkung auf 0-1- Tage alte Eier der agyptischen Baumwolleule, Spodoptera littoralis (Boisd.) untersucht und ihre LC5,-Werte bestimmt. Decis war unter den Pyrethroiden die aktivste Verbindung, gefolgt von Dowco 417, Cymbush, Pydrin und Ambush; Cybolt war vie1 schwacher wirksam. Die Benzoyl- Phenylurea-Chitinsynthese-Hemmer Dimilin und PH 60-40 waren bei 5 ppm wirksamer als alle getesteten Pyrethroide auger Decis and Cymbush, jedoch immer noch weniger giftig als das wirksamste Pyrethroid, Decis, bei 1 ppm. Einige weitere Benzoyl-Phenylurea-Verbindungen, wie z. B. PH 60-45, Dowco 439 and Dowco 401, waren gegen S. littoralis Eier entweder nur schwach aktiv oder unwirksam.

References

ABO-ELGHAR, M. R.; EL-KEIE, I. A.; MITRI, S. H.; RADWAN, H. S., 1980: Field evaluation of certain insecticides for ovicidal activity of [against] the cotton leafworm, Spodopteru littoralis (Boisd.). Z. ang. Ent. 89, 100-104.

ABO-ELGHAR, M. R.; RADWAN, H. S.; AMMAR, I. A. M., 1976: The ovicidal effect of a chitin biosynthesis disru tor on Spodoptera littoralis egg masses. Third Egyptian Pest Control Conference, Ain SEams Univ., section B, lecture No. 13.

ASCHER, K. R. S., MOSCOWITZ, J., 1970: The ovicidal effect of chlorphenamidine (Fundal) and chlorohenamidine-formetanate (Fundal forte) in the Ezvutian cotton leafworm. Soodoittera

"I I I 1 1

l i t t o r h Boisd. Z. ang. Ent. 67,'34-38. ASCHER. K. R. S.: NEMNY. N. E.. 1974: The ovicidal effect of P H 60-40 rl-/4-chloro~hendb3- , ,

(2,6-difluorobenzoyl)-ureal] in Spodoptera littoralis Boisd. Phytoparaskia 2, 131-133.

Spodopteru littoralis (Boisduval) eggs and larvae. Phytoparasitica 7, 177-184.

Spodopteru littoralis eggs and on their respiration. Pestic. Sci. 11, 90-94.

ASCHER, K. R. S.; NEMNY, N. E.; ELIYAHU, M.; ISHAAYA, I., 1979: The effect of BAY SIR 8514 on

ASCHER, K. R. S.; NEMNY, N. E.; ISHAAYA, I., 1980: The toxic effect of diflubenzuron on

AVIDOV, Z.; HARPAZ, I., (1969): Plant Pests of Israel. Israel Universities Press, Jerusalem. pp.

CHANG, S. C., 1979: Laboratory evaluation of diflubenzuron, penfluron and Bay Sir 8514 as

ELLIOT, M. (Ed.), 1977: Synthetic Pyrethroids. A.C.S. Symp. Ser. 42. ELLIOT, M.; JANES, N. F.; POTTER, C., 1978: The future of pyrethroids in insect control. A. Rev.

Ent. 23, 443-469. GROSSCURT, A. C., 1978: Diflubenzuron: some aspects of its ovicidal and larvicidal mode of action

and an evaluation of its practical ossibilities. Pestic. Sci. 9, 373-386. MAAS, W., 1978: Influence of particL size on pesticidal activity. Abstract Vol., 4th Int. Congr.

Pesticide Chemistry, Zurich, 24-28 July 1978, lecture no. VII-11. MAAS, W.; VAN HES, R.; GROSSCURT, A. C.; DEUL, D. H., 1980: Benzoylphen lurea insecticides.

in: WEGLER, R. [Ed.], Chemie der Pflanzenschutz- und Schadlingsbekamprungsmittel. Vol. 6. Springer-Verlag, Berlin. pp. 423-470.

MULDER, R.; GIJSWIJT, M. J., 1973: The laboratory evaluation of two promising new insecticides which interfere with cuticle deposition. Pestic. Sci. 4, 737-745.

OLIVER, J. E.; DEMILO, A. B.; BROWN, R. T.; MCHAFFEY, D. G., 1977: A13-63223: a highly effective boll weevil sterilant. J. econ. Ent. 70, 286-288.

PHILIPS-DUPHAR BV, undated, ca. 1975: Dimilin: a new insecticide interfering with chitin deposition. Technical information. Mimeographed information brochure. %-Graveland, The Netherlands, No. 6-579180. 43 pp.

327-332.

female sterilants against the house fly. J. econ. Ent. 72, 479-481.

Toxicity of some novel pesticides for eggs of S . littoralis 509

- 1979: Preliminary technical report (1) on PH 60-43, P H 60-44, and PH 60-45 - experimental

- undated, ca. 1980: Technical information on P H 60-43, an experimental insecticide. Mimeo-

- unLted, ca. 1980a: Technical information on PH 60-44, an experimental insecticide. Mimeo-

PICKENS, L. G.; DEMILO, A. B., 1977: Face fly: inhibition of hatch by diflubenzuron and related

TALHOUK, A. M. S., 1969: Insects and Mites Injurious to Crops in Middle Eastern Countries. Paul

Various authors, 1977: Symposium on the new applications of pyrethroids (11 articles). Pestic. Sci.

Various authors, 1980: Symposium on recent advances in the chemistry of the pyrethroids (20

insecticides. 4 pp.

gra hed information brochure. 8 pp.

graphed information brochure. 9 pp.

analogues. J. econ. Ent. 70, 595-597.

Parey, Hamburg. pp. 188-190.

8, 236-384.

articles). Pestic. Sci. 21, 102-289.

Authors' addresses: K. R. S . ASCHER, M. ELIYAHU and N. E. NEMNY, Division of Toxicology, ARO, The Volcani Center, Bet Dagan 50-250, Israel; Dr. I. ISHAAYA, Division of Entomology, ARO, The Volcani Center, Bet Dagan 50-250, Israel

Institut fur Phytomedizin, Swiss Federal Institute of Technology, Zurich, Switzerland

Searching parasitoids of Dams oleae (Gmel.) (Dipt., Tephritidae) in South Africa

By P. NEUENSCHWANDER

Abstract The survey was conducted on cultivated olives in the south-western Cape Province, and on several wild olive species in the Cape Province and Transvaal from March to May 1981. Though Dacus oleae (Gmel.) was found in all areas, its occurrence on wild olive trees (OIea europaea africana only) was irregular. O n wild olives, mortality of eg s and oung larvae was high, and parasitiza- tion rates low. O n cultivated olives, D . oleae seemed less agundant than under similar conditions in the Mediterranean Basin. Mortality of young stages was low. Parasitization rates were relatively high even in orchards which had been treated against other insect pests which are not known from the Mediterranean Basin. The additional high mortality of old larvae was attributed to host- feeding b adult parasitoids. A rich parasitoid corn lex was reared, for whose identification an illustratedr key is given. The ectophagous braconic! Bracon celer Szepl. was by far the most abundant species. For unknown reasons it failed to reproduce in the insectary in Athens. Care was taken to exclude the phytophagous Eurytoma species, which emerge from the olives together with the D . oleae parasitoids, from shipments to Europe.

1 Introduction

Dacus oleae (Gmel.) is the most important pest insect on olives in most parts of the Mediterranean Basin. In these countries it is attacked by a parasitoid complex which is rather small and often inefficient. Since the beginning of the century, the idea of introducing exotic parasitoids has therefore been ad-

U.S. .Copyright Clearance Center Code Statement: 0044-2240/82/9405-0509 $ 02.50/0 2. ang. Ent. 94 (1982), 509-522 0 1982 Verlag Paul Parey, Hamburg und Berlin ISSN 0044-2240 / Intercode: ZANEAE