The efficacy of nematicides, solar heating and the fungus paecilomyces lilacinus in controlling root-knot nematode Meloidogyne javanica in Iraq

Contents - Previous - Next

Z.A. Stephan, I.K. Al-Maamoury, A.H. Michbass

Plant Protection Res. Centre, Abu-Ghraib, Baghdad, Iraq

Abstract

All tested nematicides, solar healing and Paecilomyces lilacinus reduced numbers of the root-knot nematode Meloidogyne javanica on cucumber and eggplant. Methyl bromide (40 g/m²), solar healing, fenamiphos liquid (5 cc/m²) and isazofos (25 g/m²) proved to be the most effective. Oxamyl, dazomet and the fungus application showed least satisfactory effects, with no significant differences in yield compared with the control. However, Carbofuran gave reasonable results when used at concentration (15 g/m²)

Introduction

In Iraq, M. javanica is widely distributed, causing economically significant crop losses (1, 2, 9, 18). Soil disinfestation with nematicides, heat and other radical treatments have been used as successful management tools in controlling nematode pests. Soil fumigants have proved to be effective in eradication of Meloidogyne sp. and Tylenchulus semipenetrans (4, 14). Also, oximacarbamate and organophosphate compounds have been used against plant parasitic nematodes (5, 13, 15).

In Iraq, results from soil disinfestation with nematicides and heating are still limited. Therefore, this study was carried out to determine the effect of various nematicides and some cultural methods for suppressing root-knot nematode populations in cucumber and eggplant roots and soil.

Materials and methods

The first experiment was conducted in commercial greenhouses in Rashidiya, 40 km North of Baghdad, during the years 1984-85 and 1985-86.

A 6 000 m² plot, heavily infested with M. javanica (Treub) Chit., was chosen and sub-divided into many treatments of 150 m² in a randomized complete block design and replicated four times.

Nematicides used in this experiment were carbofuran 5 percent a.i., (2,3dihydro-2,2-dimethylbenzofuran-7-yl methylcarbamate) 15 g a.i./m²; isazofos 10 percent a.i., (0-5-chloro-1-isopropyl-lH-1,2,4-triazol-3-yl O. Odiethyl phosphorothioate) 25 g a.i/m²; oxamyl 10 percent a.i., (N,N-dimethyl-2-methylcarbamoyloxyimino-2-(methylthio)acetamide) 7 g a.i./m²; and dazomet 98 percent a.i. (3,5-dimethyl-1,3,5-thiadiazinane-2-thione) 50 g a.i./m². They were spread on the surface and thoroughly incorporated into top 20-25 cm four weeks before planting.

Fenamiphos liquid 40 percent a.i., (ethyl 3-methyl-4-(methylthio)phenyl isopropylphosphoramidate) 5 cc a.i./m²: was added to the soil (irrigation water) four weeks before planting.

Methyl bromide (bromomethane) was applied to the soil at the rate of 40 g/m² using a gasproof plastic cover. Treated soil was aerated for two weeks before planting.

Solar heating was carried out by covering the soil with polyethylene plastic (new transparent and black) during the months of August and September after soil preparation and irrigation.

The fungus Paecilomyces lilacinus (Thom) Samson, which was obtained from the International Potato Centre, Lima, Peru, was applied at the rate of 40 g of fungus-infected rice grains/m² one month before planting. The inoculum was evenly spread 20-25 cm deep in the soil and covered well before planting.

The second experiment was carried out at the Agricultural Technology Institute in Mussaib, 70 km East of Baghdad, during 1985-1986.

A field heavily infested with M. javanica was selected for the test using completely randomized design. Each treatment was 60 m² and replicated four times.

All nematicides, solar heating and the fungus were applied as in the first experiment, except methylbromide was omitted.

Fifty plants of both four-week-old cucumber (Cucumis sativus L. cv. Maram) and eggplant (Solanum melongena L. cv. Local), were transplanted in the first and second experiments, respectively.

Plants were allowed to grow until the end of fruiting time (about 210 days for cucumber and 270 days for eggplant) and the weight of mature fruits per weekly harvest was recorded. At the end of the season, the percentage of plant infection and dead plants, and number of nematodes/g soil and roots were also determined. The results were statistically analysed.

Results

Experiment 1: All treatments significantly (P = 0.05) increased the yield of cucumber and decreased nematode population, compared with the control (Table 1). However, fenamiphos and methyl bromide proved to be the best, followed by solar heating. The average yield was 319, 308 and 290 kg/replicate, respectively.

Percentage of plant infection was also significantly (P = 0.05) reduced in all treatments, except for dazomet, oxamyl and the fungus P. Iilacinus (Table 1).

Experiment 2: Results of this experiment indicated that new transparent film cover, fenamiphos, and isazofos were the most effective methods for controlling the nematode. They significantly (P = 0.05) increased the average yield of eggplant compared with the control (Table 2). Results indicated that nematode populations, percentage of plant infection, and percentage of dead plants also were significantly reduced.

On the contrary, plots treated with oxamyl, dazomet and the fungus P. Iilacinus showed no significant differences in yield and nematode population in soil and roofs, compared with the control (Table 2).

Discussion

Results of both experiments showed that all tested nematicides, solar heating and fungus application were differentially effective against root-knot nematodes. Methyl bromide, fenamiphos, new transparent and black film cover and isazofos were always statistically battter than the control, supporting previous findings (3, 7, 12). Dazomet, oxamyl and carbofuran gave the least satisfactory control, which appears to be unusual as many reports (10,11, 16) have indicated successful results. These contradictory results could be due to the high soil temperature of greenhouse and Geld soils (>35°C) at the lime of application, which increased the rate of chemical breakdown of these substances. Bunt (6) reported that vydate markedly decreased the number of PratyIenchus penetrans in and outside roots at low soil temperature, but its effect was reversed at high soil temperature.

Jatala (8) reported that P. Iilacinus was highly effective against root-knot nematode, and suggested its use as a biological tool for this pest. However, our present study did not support his findings This could be due to the reverse effect of high soil temperature on fungus development. Stephan and Shams Al-din (17) indicated that the fungus did not develop well and failed to produce spores at 32°C or higher.

It should be stated that fenamiphos, solar healing and isazofos showed no harmful effect on the plants, but gave partial nematode control. The number and size of the root-galls and percentage of plant infection after seven to nine months from date of transplanting were highly reduced. In these cases, infection may have occurred near the end of the season, at which time the nematode has no great effect on plant growth and yield.

References

1. Al-Hassan, K. K., Z. A. Stephan, A. H. Alwan, A. H. Bandar, and A. W. Hamdi. 1977. Testing some tomato varieties and nematicides against Meloidogyne sp., the cause of root-knot disease. Yearbook of Plant Protection Research 1:332-357.

2. Al-Saaedy, H. A .M. 1985. Study on root-knot disease caused by nematode Meloidogyne spp. on eggplant in Iraq. M. Sc. Thesis, College of Agriculture, Baghdad University, 101 pages.

3. Badra, T. and D. M. Elgindi. 1979. Single and double combinations of nematicides against Rotylenchulus reniformis and Tylenchulus semipenetrans infecting cowpea and citrus. Revue Nematol. 2:23-27.

4. Bains, R. C. 1964. Controlling citrus nematode with DBCP increases yields. Calif. Citrogr. 49:222-233.

5. Bains, R. C. and R. H. Small. 1974. Evidence of modes of action of oxamyl nematicides on Tylenchulus semipenetrans. J. Nematol. 6:135 (Abstr.).

6. Bunt, J. A. 1973. Influence of temperature on the population density of Pratylenchus penetrans and the growth response of Pyrus malus L. seedlings, after a soil drench with S-methyl 1- (dimethyl- carbamoyl)-N-((methylcarbamoyl) oxy) thioformimidate. Med. Fak. Land. Gent. 38:1259-1274.

7. Hassan, M. S. 1982. Sterilization of soils in plastic houses by the use of solar heating. M. Sc. Thesis, Agri. College, Baghdad University, 103 pages.

8. Jatala, P. 1985. Biological control of nematodes. Pages 303-308 In: An advanced treatise on Meloidogyne (biology and control). Vol. I, J.N. Sasser and C.C. Carter (eds.), North Carolina Stale Univ. Graphics.

9. Katcho, Z. A., A. H. Alwan, and A. H. Bandar. 1976. Root-knot nematodes their hosts in Iraq. Bull. Nat. His. Res. Centre 7:38-41.

10. Krishnaprassad, K. S. and K. Krishnappa. 1981. Effect of bare roof dip treatments with pesticides on Rotylenchulus reniformis affecting Brinjal. Indian J. Nematol. 11:154- 158.

11. Lamberti, F. 1975. Fumiganti nematicidi sistemici nella lotta contro Fitoelementi Ipogei. Rep. S.I.F. 26.

12. Lamberti, F. 1979. Chemical and cultural methods of control. pp. 405423. In: Root-knot Nematodes (Meloidogyne species) Systematics. biology and control. F. Lamberti and C.E. Taylor (eds.), Academic Press, N.Y.

13. Oteifa, B., D. M. Elgindi, and M. S. Eleragi. 1971. Evaluation of oxamyl granular systemic nematicides for the control of Rotylenchulus reniformis on Egyptian cotton. Res. Bull. Fac. Agric., Ain-Shams Univ.: 113.

14. Raksi, D. J., N. O. Jones, J. J. Kissler, and D. A. Luvisi. 1975. Further results from deep placement fumigation for control of nematodes in vineyards. Pl. Dis. Reptr. 59:345-349.

15. Scotto La Massese, C. and P. Roussel. 1975. Action furadan et phenimiphos sur le taux de multiplication d'Heterodera restochiensis et sur les rendements d'une culture pr 2icoce de pomme de terre. Phyriat Phytophtarm. 24:25-36.

16. Stephan, Z. A. and D. L. Trudgill. 1983. Effect of time of application on the action of foliar sprays of oxamyl on Meloidogyne hapla in tomato. J. Nematol. 15:96-101.

17. Stephan, Z. A. and S. Shams Al-Din. 1987. Influence of temperature and culture media on the growth of the fungus Paecilomyces lilacinus. Revue Nematologie (in press).

18. Stephan, Z. A., A. H. Alwan, and A. S. Al-Beldawi. 1977. General survey of root-knot nematode, Meloidogyne sp., on tobacco in Iraq. Yearbook of Plant Protection Res. 1:284-294.

Table 1. Effect of nematicides, solar heating, and Paecilomyces lilacinus on cucumber production, plant infection and numbers of Meloidogyne javanica

1 Each number is a mean of four replications. Values followed by different letters are different at P=0.05.

Table 2. Effect of nematicides, solar heating and Paecilomyces lilacinus on eggplant production, plant infection and numbers Meloidogyne javanica

Contents - Previous - Next