IOBC wprs Bulletin Vol 22(9), 1999

Mating disruption tests to control Sparganothis pilleriana (Schiff.) (Lepidoptera: Tortricidae)

Anne Schmidt-Tiedemann, Friedrich Louis, Takehiko Fukumoto,1 Claus P. W. Zebitz2 and Heinrich Arn3

Abstract - Sparganothis pilleriana Schiff. is a tortricid moth causing occasional but serious damage to grapevines. Chemical control is often inefficient due to the particular life habits of the caterpillars. For this reason we have carried out pilot experiments with themating disruption technique. Four blend compositions containing pheromone components of Sparganothis pilleriana were tested. The mixture of E-9-dodecenylacetate, Z-9-dodecenylacetate, E-11-tetradecenylacetate, Z-11-tetradecenylacetate, E-9-dodecen-1-ol and Z-9-dodecen-1-ol gave best results with S. pilleriana, reducing larval infestation by 82 %.

Key words - Eupoecilia ambiguella, Lepidoptera, mating disruption, sex pheromone, Sparganothis pilleriana, Tortricidae, viticulture

Introduction

Sparganothis pilleriana Schiff. is present as a pest in grapevine throughout the world. The larvae feed on buds, leaves, inflorescences and young berries of grapevine, occasionally causing serious damage and decreasing yields. Since the beginning of the nineties increasing damage of this tortricid pest became an important problem in some viticultural areas of Germany, especially in the Palatinate (Schirra and Louis 1995).

Control of S. pilleriana with insecticides is difficult due to the particular life cycle of the pest: In spring it can take six weeks before all larvae have left their overwinterung places located under the bark of the vine. This makes it extremely difficult to find the best timing for application of insecticides. Furthermore the larvae form feeding shelters of leaves in which they live and hide.

Due to these problems in summer 1996 a research program was initiated at the Staatlilche Lehr- und Forschungsanstalt für Landwirtschaft, Weinbau und Gartenbau (SLFA), Neustadt/ Weinstraße, Germany. 1996. In the framework of this project, the biology of S. pilleriana is being examined in detail with the hope to develop effective and environmentally safe control methods. The research emphasis has been placed on the disruption of sexual communication and mating by synthetic pheromones (mating disruption technique).

The importance of E-9-dodecenyl acetate (E9-12Ac) and E-9-dodecen-1-ol (E9-12OH) in sex pheromone communication of S. pilleriana was recognized in electrophysiological and field studies (Saglio et al. 1977, Roehrich et al. 1977). Chemical analysis followed by field studies revealed the importance of two additional sex gland components, E-11-tetradecenyl acetate (E11-12Ac) and Z-11-tetradecenyl acetate (Z11-14Ac) (Guerin et al. 1986); E9-12OH was found to be essential for attraction, but was not detected in the extracts. Based on this knowledge, we have tested various blends of chemicals in the field formating disruption against S. pilleriana. From the beginning, we included Z-9-dodecenyl acetate (Z9-12Ac), the main pheromone component of the grape berry moth, Eupoecilia ambiguella Hbn., in the mixtures. This species is already controlled successfully with a mixture of Z9-12Ac and E9-12Ac, and our hypothesis was that it could be possible to find a blend capable of disrupting both vineyard insects.

Materials and Methods

In 1996, chemicals were dispensed from pieces of polyethylene tubing (0.7 mm ID, 1.4 mm OD, 20 cm long), stapled to wooden supports and containing 60 mg of chemical each (Arn et al. 1976). Chemicals were supplied by Bedoukian (Siber Hegner Raw Materials Ltd., Zürich, Switzerland). In the following years dispensers were formulated by Shin-Etsu Chemical Company, Tokyo, Japan. The dispensers were loaded with 85 mg pheromone components per rope and the dosage was 1000 dispenser per hectar.

To monitor the effect of the pheromone treatments on male captures, trap stations were placed consisting of 3 traps each baited with synthetic pheromone and one or two (Table 1 and 2) female-baited trap. Pheromone lures contained 20 µg each of E9-12Ac, E11-14Ac and Z11-14Ac plus 5 µg E9-12OH on a gray rubber cap in a formulation supplied by Phero. Net (Andermatt Biocontrol AG, CH-6146 Grossdietwil). Female-baited traps contained a small cage containing a virgin female. Tetra traps (ARN et al. 1986) were used baited with pheromone or a virgin female.

The effect of the treatments on the pest population was determined by counting egg masses after the peak of moth flight in July/August. This was done by sampling 20 (1997) or 40 neighboring vines (1998) chosen at various locations throughout the plot in several replications (Table 1 and 2). In addition, larval infestations were determined in spring of 1998. For this, a square of 150 m2 was left untreated with insecticide in each plot and the 40 vines in the center were evaluated.

Results

Pilot experiments were conducted in 1996 using E9-12Ac exclusively and a mixture of E9-12Ac and Z9-12Ac. A vineyard of 2,25 ha was devided into 12 equal sections. In the center of each section, a plot of 200 m< was used for the experiment. The plots were separated by at least 45 meters. Two plots were treated with each treatment. Six of the plots were left untreated. The two remaining plots were reserved for other tests. The amount of chemical applied was 25 dispenser per plot (60 mg per dispenser = 7,5 g/ha). Trap shutdown was measured with 2 pheromone traps in each plot.

Treatment with E9-12Ac led to 86 % suppression of trap catches (average catch 12,8 moths/trap compared with 91,8 moths/trap in the control plots. With the isomer mixture, suppression was 83 % (average catch 15,3 moths/trap). This indicated that E9-12Ac could be an effective mating disruptant and that addition of Z9-12Ac for E. ambiguella has no negative effect on the disruption of S. pilleriana.

Table 1. Composition of disruptant blends used in 1997 (relative amounts)

The effect of the pheromone treatment was followed with pheromone traps, female baited traps, and by counting egg masses. Furthermore squares of about 150 m< (72 vines) were left untreated with insecticides so that the larval infestation rate could be determined in the spring of 1998. Three of these squares were positioned in the pheromone plot and one in each control plot. In the center of each square 40 vines were examined to determine the number of larvae per vine.

Tests with blends being more complex (Table 1) were made with Shin-Etsu-dispensers in 1997 in two locations in the South Palatinate. In site 1 a 5 ha plot was treated with blend 1. One control plot was selected 100 m against the main wind direction; a second control plot was located about 200 m downwind. In site 2, blends 2, 3 and 4 were tested in 1 ha plots. The plots were arranged in blocks separated by buffer zones. Control plots were located at distances of 70 and 100 m, respectively, against the main wind direction. Three pheromone-baited traps and one virgin-female trap were placed in the center of each disruption plot and the control plots. As in site 1 disruption efficacy was determined by counting the eggmasses of 20 vines. This was repeated 9 times in each pheromone plot and a total of 15 times in the control plots. In each plot a square of 150 m< was not treated with insecticides in which the centered 40 vines were evaluated to determine the infestation rate with larvae in spring 1998.

In site 1 the pheromone treatment with blend 1 caused a reduction in trap catches of moths of 99,8 % in the pheromone baited traps and of 100 % in the traps with an unmated female in comparison to the control plots not treated with pheromone (Table 2). The results obtained at site 2 with blend 2 to 4 were similar. The trap catch reduction in trap type 1 and 2 were 100 % with blend 2, 98,8 % and 100 % with blend 3 and 97,7 % and 95,5 % with blend 4.

Table 2. Effect of disruptant treatments on S. pilleriana in 1997.

	Treatments 1997
	Site 1		Site 2
	1	Control	2	3	4	Control
Plot size (ha)	5		1	1	1
No. pheromone traps	9	6	3	3	3	6
Average catch (± SD) per pheromone trap	0.1 ±0.3	50.5 ±15.4	0	0.7 ±1.2	1.3 ± 1.5	59.8 ±14.8
No. virgin female traps	3	3	2	2	2	3
Average catch in virgin female traps	0	16.7	0	0	0.5	21.7
No. vines examined for egg masses	480	360	180	180	180	300
Average no. egg masses per vine	0.02	0.1	0.03	0.03	0.08	0.34
No. vines examined for larvae	110	80	40	40	40	80
Average no. larvae per vine	1.2	6.4	2.5	3.13	2.7	7.3

Sd = Standard deviation

The good effectiveness of the pheromone substances could be confirmed in the distribution of eggmasses. Using blend 1, 2 or 3 the reduction of the number of eggmasses ranged from 85,8 to 91,8 % compared to the control plots (Table 2). The degree of effectiveness of blend 4 was a little lower (75,4 %).

Table 2: Effect of disruptant treatments on S. pilleriana in 1998.

	Treatments 1998
	Site 1		Site 2
	1	Control	1	Control
Plot size (ha)	5		5
No. pheromone traps	9	9	12	9
Average catch (± Sd) per pheromone trap	0.2± 0.4	49.2± 16.4	0.9± 0.9	90.7± 19.1
No. virgin female traps	3	3	3	3
Average catch in virgin female traps	0.3	33	0.3	49.7
No. vines examined for egg masses	120	120	160	120
Average no. egg masses found	0.05	1.6	0.8	5.3

Sd = Standard deviation

The evaluation of the larval infestation rate showed that the treatment with blend 1 caused the best degree of effectiveness reaching 82 % (Table 2). Blend 2, 3 and 4 reduced the number of larvae per vine in a range from 57 to 66 % in comparison to the control plots not treated with pheromones.

The differences in reducing the infestation rate between blend 1 and blend 2-4 may depend on the size of the plots which were five hectars for blend 1 and each one hectar for blend 2 to 4. Other reasons can be distinct conditions concerning the population density of predators and parasites in site 1 and site 2.

The reduction of moth catches was between 99 % and 100 % in pheromone baited traps and in traps each with an unmated female compared to the untreated control plots (Table 2). The degree of effectiveness on the decrease of the egg masses was 97 % in site 1 and 85 % in site 2. The lower effectiveness in site two can be explained by the fact that the moth flight was already more advanced in site two when the dispensers were placed in the field and some matings took place before the beginning of the treatment.

Conclusion

The results of these experiments show that the tortricid S. pilleriana can be controlled quite successfully by mating disruption with blends of pheromone components. Adding Z9-12Ac to the disruptant blend does not seem to reduce the disruptant effect which indicates that it might be possible to use disruptant cocktails for both S. pilleriana and E. ambiguella. Further studies on the efficacy of these blends in controlling these 2 species need to be conducted, especially on a larger scale.

Acknowledgements

The investigations were made possible by financial support from the Ministry of Economy, Transportation, Agriculture and Viticulture of Rheinland-Pfalz, Germany.

References

Arn, H., Delly, B., Baggiolini, M. & Charmillot, P. J. 1976: Communication disruption with sex attractant for control of the plum fruit moth, Grapholitha funebrana: a two-year field study. Entomol. exp. appl. 19: 139-147.

Arn, H., Rauscher, S., Buser, H. R. & Guerin, P. M. 1986: Sex pheromone of Eupoecilia ambiguella female: Analysis and male response to ternary blend. J. chem. Ecol. 12: 1417-1429.

Guerin, P. M., Buser, H. R., Tóth, M., Höbaus, E., Schmid, A. & Arn, H. 1986: Sex pheromone of Sparganothis pilleriana: E- and Z-11-tetradecenyl acetates as essential components. Entomol. exp. appl. 40: 137- 140.

Roehrich, R. 1977: Compte-rendu de la réunion sur les phéromones sexuelles des insectes, Montfavet 25-27 octobre 1977, INRA Montfavet.

Saglio, P., Priesner, E., Descoins, C. & Gallois, M. 1977: A synthetic attractant for the grape pyralid Sparganothis pilleriana (Schiffermüller) C. R. Hebd. Seances Acad. Sci., Ser. D Sci. Nat. 284, 20: 2007 - 2010.

Schirra, K.-J. & Louis, F. 1995: Auftreten von natürlichen Antagonisten des Springwurmwicklers Sparganothis pilleriana in der Pfalz. Deutsches Weinbaujahrbuch 46: 129 -140.

Schmidt-Tiedemann, A., Louis, F., Zebitz, C. P. W. & Arn, H. 1999: Pheromone - Ein Ansatz zur umweltschonenden Bekämpfung des Springwurms (Sparganothis pilleriana Schiff.). Deutsches Weinbaujahrbuch 50: 153-158.

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