Trap crops for some pests of the Asia Pacific lowland tropics

R. Muniappan, T.S. Lali and Prem Singh Agricultural Experiment Station University of Guam Mangilao, Guam 96923 U.S.A

Abstract Trap cropping with cv. Tempest, cv. Minowase Summer Cross 3 and Indian mustard in cabbage field has significantly reduced the incidence of Hellula undalis (F.) pavonana (F.) and Halticus tibialis (Reuter) on cabbage. There is a direct relationship to the infestation of H. undalis to the incidence of soft rot disease of cabbage in the field.

Key words: Trap crops, cabbage, Hellula undalis, Crocidolomia pavonana, Halticus tibialis, mustard, radish, Chinese cabbage.

Introduction H. tibialis were counted from 10 plants selected at Cabbage ( oleracea var. capitata L) on Guam random in each row at weekly intervals for 10 weeks. is attacked by 10 pests (Muniappan and There was no incidence of diamondback , Plutella Marutani, 1992). Most of these pests also occur in the xylostella (L.) and aphids during the period of this lowland tropics of the Asia Pacific region (Waterhouse experiment. and Norris, 1987, 1989; Waterhouse, 1993). Attempts to tackle these pests by environmentally safe, effective Results and Discussion and economical methods lead to the research on trap H. undalis larvae were mostly found on radish and cropping. Successful use of trap crops for control of mustard in the cabbage plot with trap crops (Figure 1). rape blossom beetle, Meligethes aeneus on There was significantly more H. undalis on the in Finland (Hokkanen, 1989; Hokkanen et al., 1986) cabbage plants in the plot without trap crops than the and diamondback moth on cabbage in Bangalore, India one with the trap crops (Figure 2). The incidence of (Srinivasan and Krishna Moorthy, 1991) have been the disease, soft rot on cabbage in the nontrap cropped reported in cruciferous crops. Hokkanen (1991) has plot was 34.5% higher than in the trap cropped plot reviewed use of trap crops for control of pests in (Figure 3). Al-Janabi et al. (1990) also found a positive different cropping systems. Muniappan and Marutani relationship to H. undalis bore holes and associated (1992) and Silva-Krott et al. (1995) have indicated the secondary infestation to the incidence of soft possibility of use of Chinese cabbage, radish and rot in Kohlrabi in Iraq. Indian mustard as trap crops in cabbage fields for The incidence of C. pavonana was more on the control of cabbage webworm, Hellula undalis (F.) trap crops than on cabbage in the trap cropped plot cabbage cluster caterpillar, Crocidolomia pavonana (Figure 4). Heavy incidence of C. pavonana on (F.) flea hopper, Halticus tibialis (Reuter) and the mustard trap grown next to cabbage resulted in mustard aphid, Liphaphis erysimi (Davis). In this migration of the caterpillars from mustard to cabbage. paper, we present the incidence of pests and soft rot Some caterpillars were also blown over by wind from disease in the cabbage fields with and without trap the mustard to the cabbage plants (Figure 5). crops. H. tibialis was found only on the trap crops. The heaviest infestation occurred on the radish. The trap Materials and Methods crops used in this experiment did not have any Experiments were conducted on two field plots (11.2 attraction to S. litura. More S. litura larvae were found x 16.2 m) located 80 m apart from each other at the on cabbage than in the trap crops however there were Inarajan agricultural farm. In each plot, 10 rows were more larvae in the cabbage plots without the trap crops transplanted with one month old cabbage seedlings cv. than the one with the trap crops (Table 1). K K Cross at a spacing of 1.2 m between and 0.35 m The trap crops, Chinese cabbage, radish and within rows. Trap crops one row each of Chinese Indian mustard were effective in reducing the cabbage cv. Tempest, radish cv. Minowase Summer incidence of H. undalis, C. pavonana and H. tibialis Cross 3, and Indian mustard, were planted on either in cabbage plantings. The reduction in infestation of side of the upwind plot. These trap crops were H. undalis in cabbage also reduced the incidence of transplanted two weeks prior to the planting of cabbage soft rot. Mustard row should be the outermost one in seedlings. the trap crops or adequate spacing between cabbage Larvae of H. undalis, C. pavonana and and mustard should be given to avoid caterpillars being Spodoptera litura (F.) and adults and nymphs of blown by wind on the cabbage plants.

Biologically-based technologies 139 No. of H. undalis larvae/10 plants 70 ▲ ◆ On cabbage with traps 60 ▲ On cabbage without trap crops

50

40 ▲ ▲ ▲ 30 ▲ ▲ 20 ▲

10 Figure 1. Hellula undalis ◆◆ larvae in the cabbage plots ▲ ▲ 0 ▲◆ ◆◆◆◆◆◆◆ with and without trap crops 4/9/96 4/16/96 4/22/96 4/30/96 5/6/96 5/14/96 5/22/96 5/28/96 6/3/96 6/9/96 Dates

No. of H. undalis larvae/10 plants 16

◆ ◆ Radish 14 ◆ ࠗ Tempes 12 ▲ ▲ Mustard

X Cabbage 10 ◆ ◆ 8 ◆ ◆ ▲ 6 ▲ ◆ ◆ 4 XX ▲ࠗ 2 Figure 2. Hellula undalis ࠗ ◆ ▲ ࠗ ▲ ࠗ larvae in the trap cropped 0 ◆▲ࠗࠗX ▲▲ࠗXXXXXXX▲ࠗࠗ ࠗ field 4/9/96 4/16/96 4/22/96 4/30/96 5/6/96 5/14/96 5/22/96 5/28/96 6/3/96 6/9/96

Dates

% Heads Infected 70 Table 1. Incidence of Halticus tibialis and Spodoptera litura in the cabbage field with and without trap crops 60 / H. tibialis S. litura 50 treatments Mean S.E. Mean S.E. 40 Cabbage crop1 0 0 1.5 0.3 2 30 Cabbage crop 0 0 3.9 0.5 Radish 26.1 0.4 0 0 20 Tempest 1.6 0.6 0.2 0.2 Mustard 2.7 0.5 0.2 0.2 10 1Cabbage with trap crops 2Cabbage without trap crops 0 Cabbage Cabbage with without traps traps

Figure 3. Cabbage heads infested with soft rot in the plots with and without trap crops

140 Proceedings: The Management of Diamondback Moth and Other Crucifer Pests No. of C. povanana larvae/10 plants 4 ࠗ On cabbage with trap crops ࠗ 3.5 ● On cabbage without trap crops

3

2.5 ● ● 2 ࠗ● ࠗ 1.5 ● ࠗ

1

0.5 ࠗ ● ࠗ ● ࠗ ● 0 ࠗࠗ●● ● ࠗ 4/9/96 4/16/96 4/22/96 4/30/96 5/6/96 5/14/96 5/22/96 5/28/96 6/3/96 6/9/96

Dates Figure 4. Crocidolomia pavonana larvae in the trap cropped field

No. of C. pavonana larvae/10 plants 80 ◆ Radish 70 ▲ ࠗ Tempest ▲ ࠗ 60 ▲ ▲ Mustard

◆ 50 X Cabbage

40

30 ࠗ ࠗ ࠗ ◆ ◆ ࠗ 20 ◆ ▲ ◆ 10 ࠗ ▲ ▲ ▲ X X X ◆◆ 0 XX◆ X X ▲ࠗࠗࠗࠗX ▲▲X◆◆X 4/9/96 4/16/96 4/22/96 4/30/96 5/6/96 5/14/96 5/22/96 5/28/96 6/3/96 6/9/96 Dates Figure 5. Crocidolomia pavonana larvae in cabbage plots with and without trap crops

Acknowledgement ÐÐÐÐ (1991). Trap cropping in pest management. Annual Funding for research was provided by the project Review of Entomology 36: 119Ð138. GUA000103 and in part by the USDA under CSREES Hokkanen, H., Granlund, H., Husberg, G. G., and Markkula, Special Grant agreement No. 93Ð34135Ð8827 M. (1986). Trap crops used successfully to control Meligethes aeneus (Col., Nitidulidae), the rape blossom managed by Pacific Basin Administrative Group beetle. Annales Entomologici Fennici 52: 115Ð120. (PBAG). Muniappan, R. and Marutani, M. (1992). Pest management for head cabbage production on Guam. Proceedings of References the Second International Workshop on Diamondback Al-Janabi, G. D., Al-Azawi, A. F and Tamimi, T. (1990). Moth and other Crucifer Pests, Tainan 1990, pp 541Ð Some important pests of kohlrabi and their possible role 549. in dissemination of soft bacterium in Iraq. Arab Journal Silva-Krott, I. U., Singh, P., Lali, T. S., and Muniappan, R. of Plant Protection. 8: 25Ð29. (1995). Development of a trap cropping system for Hokkanen, H. M. T. (1989). Biological and agrotechnical cabbage in Guam. Pest Management in Horticultural control of the rape blossom beetle, Meligethes aeneus Ecosystems 1: 27Ð35. (Coleoptera, Nitidulidae). Acta Entomologica Fennica 53: 25Ð29.

Biologically-based technologies 141 Srinivasan, K. and Krishna Moorthy, P. N. (1991). Indian mustard as a trap crop for management of major lepidopterous pests on cabbage. Tropical Pest Management. 37: 26Ð32. Waterhouse, D. F. (1993). The Major Arthropod Pests and Weeds of Agriculture in Southeast Asia. ACIAR, Canberra 141 pp. Waterhouse, D. F. and Norris, K. R. (1987). Biological Con- trol-Pacific Prospects. Inkata Press, Melbourne, 454 pp. Waterhouse, D. F. and Norris, K. R. (1989). Biological Con- trol-Pacific Prospects Ð Supplement 1, ACIAR, Canberra 123 pp.

142 Proceedings: The Management of Diamondback Moth and Other Crucifer Pests