32 MaYgorzata Skrzypczyriska

TUBEUF, C., 1930: Schutz vor der Einschleppung von Nadelholzschadlingen mit den Samen. Z. f. Pflanzenkr. u. Pflanzensch. 40, 521-526.

VIKBERG, V., 1966: Observations on some Finnish species of Megastigmus Dalman (Hyrn., Torymidae), including the biology of Megastigmus bipunctatus (Swederus). Ann. Ent. Fenn.

WI~CKOWSKI, S., 1957: Wyniki hodowli pasoiyt6w owad6w IeSnych. Cz+C I. Pol. Pismo Ent. 26,

WINNERTZ, J., 1853: Beitrag zu einer Monographie der Gallmucken. Linnaea Ent. 8, 154-324. WITTE, A., 1950: Skadegorelse av Plemeliella abietinu Seitn. (Dipt., Cecid.). Opusc. Enr. 15, 72. WOLFF, M.; JENSS, O., 1941: Zur Megastigmus-Frage. Z. f. Forst- und Jagdw. 23, 113-136. WOLFF, M.; KRAUSSE, A., 1922: Die forstlichen Lepidopteren. Jena: Gustav Fischer. ZASEV, B., 1959: Vfvoj obal’ovafa SiSkoviho Laspeyresia (Grapholithu) strobilella L. v Bulharsku a

jeho Skodlivost na firode sernena roku 1955. Lesn. Eas. 5, 397-408. ZASEV, B.; DASKALOVA, I.; CANKOV, G., 1962: Rezultati ot opiti za bor’ba sreifu sm’rEovija

semejad (Laspeyresia strobilella L.) Erez izpolzuvane na chimitni sredstva. NauEn. Trud. 20,

ZOCCHI, R., 1961: Contributi alla conoscenza degli insetti delle piante forestali. V. I1 Gen. Dioryctria Zell. (Lepidoptera, Pyralidae) in Italia. Redia 46, 9-143.

32, 309-315.

311-320.

79-87.

Author’s address: MAY GORZATA SKRZYPCZYNSKA, Institute of Forest Protection, Academy of Agriculture, 31-024 Krakbw, ul.Sw. Marka 37, Poland

College of Agriculture, Vellayani-69I 122, India

Insect antifeedant action of some fungicides

By P. JOHN, D. DALE and JAMES MATHEW

Abstract The insect antifeedant roperty of five commonly used fungicides - Bordeaux mixture, Dithane M45, Dithane 278, Difolaton and Hinosan - was evaluated against fourth instar Rice Swarming Caterpillar, Spodoptera m u r i t k under laboratory and field conditions. Dithane 2 7 8 was found to exhibit the maximum antifeedant action. The action persisted in field up to 20 days in the case of Dithane M45. There was a ositive correlation between reduction in larval and upal weights of the test insects on one hanjand the mean weights of leaf protected over controy, on the other.

1 Introduction

Insect antifeedants are a group of chemicals that when sprayed on to crops, do not harm the beneficial insects but at the same time protect them from various leaf-eating insect pests. Brestan is a highly effective fungicide used for the control of Cercosporu leaf spot on beets, Septoria blight of celery and Phytoph- thora late blight of potato. Incidently it was noted that the fungicide-treated fields were remarkably free from the attack of many defoliating insects. Antifeedant property of a few other fungicides has also been reported (ASCHER and NISSIM 1964). But no study has so far been undertaken in India to assess the influence of fungicide application on the consumption of foliage by insect

U.S. Copyright Clearance Center Code Statement: 0044-2240/82/9401-0032 $ 02.50/0 2. ang. Ent. 94 (1982), 32-34 0 1982 Verlag Paul Parey, Hamburg und Berlin ISSN 0044-2240 / Intercode: ZANEAE

Insect antifeedant action of some fungicides 33

pests and on its consequent effect on insects. The present study was hence undertaken to evaluate the insect antifeedant activity, if any, of five common1 used fungicides on Rice Swarming Caterpillar, Spodopteru muuritiu Boisd: (Noctuidae, Lepidoptera), a serious defoliator pest of rice.

2 Materials and methods

The fungicides used for the experiment were Bordeaux mixture, Dithane M45 (manganese eth lene bis dithiocarbamate), Dithane 278 (zinc ethylene-bis-dithiocarbamate), Difolatan (tet- racKoroethil thiophthalimide) and Hinosan (dithiophosphoric-o-ethyl-S-S-diphenyl ester) at 1 .o, 0.3, 0.3, 0.2 and 0.1 Yo active ingredient concentrations res ectively. The fourth instar larvae of S. mauritia were obtained from the culture maintained in t!e Entomology Division laboratory. Each spray solution was prepared and preweighed leaves were dip ed in it and air-dried. The leaves were then kept in water in specimen tubes using wet cotton pa&. Caterpillars were weighed and introduced into each glass trough in which the leaves were kept. For each treatment five larvae were used and each treatment was replicated thrice. Leaves sprayed only with distilled water were kept as control. The weights of caterpillars and the uneaten ortions of leaves were taken at the end of 48 h. Persistence of antifeedant activity under field con8tion was assessed by keeping sprayed rice plants in pots, collecting leaves from them periodically and providing them as food to founh instar larvae. The indices for persistence (as PT values) were calculated according to PRADHAN (1967).

3 Results and discussion

It is evident from the table that Dithane 278 had offered the maximum protection to the crop. Hinosan and Bordeaux mixture had also exhibited comparable antifeedant activity. Dithane 2 78 is a metal chelate complex coming under the chemical group of dithiocarbamates. There are alread reports showing that some of the metal chelate complexes have insect antifee d y - ant pro erty (PANDA 1979). Hinosan (Ediphenphos) is an organophosphate

fungicides inhibit chitin synthesis in sensitive cells. Even though no attempt was made in the present study to separate out the various biological effects like toxicity, chitin synthesis inhibition etc. from antifeedant action, it is expected that such effects also may contribute partly to the antifeedant action of the chemicals.

fungici B e having mode of action very much related to Kitazin. Both these

Antifeedant action of Fungicides and the effect of treatments on larval and pupal weights of Spodoptera mauritia

- 1 2 3 4 5 6

7

Treatment Mean weight Mean weight of lclf con- of leaf pro-

turned tected over (g) control(%)

Persistence" (pT values)

Mean gain in larval weight

(s)

Reduction in Mean pupal larval weight weight

controi'm) with res ectto (g)

Bordeaux mixture Dithane M-45 Dithane 2-78 Difolation Hinosan Control (for 1 and 5) Control (for 2,3 and 4)

0.46 53.0 0.40 42.8 0.23 67.1 0.49 30.0 0.38 61.2 0.98 - 0.70 -

454 488 446 215 413 - -

~~

0.043 81.6 0.148 0.096 61.6 0.156 0.125 50.0 0.132 0.248 0.8 0.214 0.098 58.1 0.180 0.234 - 0.300

0.250 - 0.305

* PT value = Average percentage of leaf weight protected over control (P) X Effective period in days (T) I

34 P. John, D . Dale and James Mathew

The persistence of antifeedant action of the fungicides was evaluated under field conditions. Dithane M45 persisted up to 20 days with 13.3 Yo leaf weight protected over control at the last observation. Even though the acute antifeed- ant action was the highest with Dithane 2 78, the fungicide ranked only third in terms of its persistence. Persistence of any test chemical depends on various extrinsic and intrinsic factors like its chemical nature, susceptibility to photo- and thermal degradations, interaction of the chemical with plant surface etc. Dithane M45 was the most persistent, followed by Bordeaux mixture and Dithane 278.

It is clear from the table that there was significant reduction in biomass formation in insects in relation to the antifeedant action of the fungicides. The maximum reduction in larval weight was noted among caterpillars fed on Bordeaux mixture-treated leaves. It is seen that reduction in pupal weight and antifeedant property are ositively related. Maximum reduction in pupal

Bordeaux mixture and Dithane M45. ASCHER and MOSCOWITZ (1969) have also observed similar reduction in pupal weight in S. littoralis caused by organotin antifeedant Pennsalt TD 5032.

The present study is a preliminary one, which has yielded valuable informa- tion useful for pest management. It would be worthwhile to test all pesticides for their alternate roles as antifeedants, chitin synthesis inhibitors, insect hormone analogues and even as plant nutrients.

weight (56.0 %) was recor s ed in insects treated with Dithane 278 followed by

Acknowledgements We wish to express our thanks to the Dean, College of Agriculture, Vellayani for providing necessary facilities. The senior author (P. J.) owes his gratitude to the Director of Agriculture, Kerala State for deputing him to undertake the study.

Zusammenfassung Uber die hemmende Wirkung einiger Fungizide auf das FreJherhalten volt Insekten

Die Eigenschaft 5 haufig verwendeter Fungizide (Bordeaux-Mischung, Dithane M45, Dithane 278, Difolatan und Hinosan) auf das Freherhalten von Spodoptera murritia 4 Larvenstadium) wurde unter Labor- und Feldbedingungen gepriift. Dithane 278 war am wir kr; amsten. Im Feld war Dithane M45 20 Tage effektiv. Es wurde eine positive Korrelation zwischen der Gewichtsab- nahme der Insektenlarven und Pu pen einerseits und dem mittleren Blattgewicht andererseits im Vergleich zur Kontrolle festgestei.

References ASCHER, K. R. S.; MOSCOWITZ, J., 1969: Pennsalt TD-5032, an experimental organotin insecticide with antifeedant properties. Int. Pest Control 11, 17-20. ASCHER, K. R. S.; NISSIM, S., 1964: Organotin compounds and their potential use in insect control. Wld. Rev. Pest. Control 3, 188-211. PANDA, N., 1979: Pest management in winter rice. Paper presented in the 66th Indian Science Congress, 1979. PRADHAN, S., 1967: Strategy of integrated pest control. Indian J. Ent. 29, 105-122.

Authors’ addresses: P. JOHN, Directorate of A iculture, Trivandrum, Kerala, S. India; D. DALE, Chemistry De artment, #e International Rice Research Institute, P.O. Box 933, Manila, Phppines; JAMES MATHEW, College of Agriculture, Vellayani, 695 522, Kerala, S. India