Abstract: The effect of horse and donkey manure and carbofuran on the population densities of three phytonematodes viz., Helicotylenchus indicus, Meloidogyne sp. (larvae) and Merlinius brevidens associated with garlic crop and garlic yield was investigated. Population densities of all three nematode species were markedly reduced by the manures but more prominently by carbofuran. Yield was substantially increased by the manures and the chemical nematicide carbofuran.
Introduction
Work on the use of non-persistent pesticides for controlling plant parasitic nematodes is being conducted the world over (Rakesh and Sharma, 1991). Among the many applications, addition of animal manures to soil is known to have beneficial effects on soil nutrients, soil physical condition, soil biological activity and crop performance (Wade and Sanchez, 1983). In addition manuring have also been investigated as an alternative method of nematode control (Akhtar and Mahmood, 1994). In the findings on management of nematodes associated with garlic Khan et al. (1998) suggested that neem seed coat and neem cake were suitable for controlling nematodes associated with garlic, resulting in significant increase in yield over controls. Similarly, Khan and Shaukat (1998) reported the efficacy of pigeon manure, sawdust and poultry manure on population of Helicotylenchus indicus, Hoplolaimus seinhorsti and Merlinius brevidens associated with garlic and reported both pigeon and poultry manure more suitable in controlling the nematodes and increasing yield as compared to sawdust. Present studies were conducted to find out the nematicidal properties of horse and donkey manures against nematodes associated with garlic and the effect of these manures or yield.
Materials and Methods
The experiment was conducted in the experimental fields of Crop Diseases Research Institute, PARC, University of Karachi. The fields had a history of wheat cultivation from the last 20 years. Garlic (Allium sativum L.) was planted in the first week of November 1998 and harvest in the third week of April 1999. The selected fields were naturally infected with Helicotylenchus indicus (Siddiqi, 1963), Meloidogyne sp. (Goeldi, 1892) larvae and Merlinius brevidens (Allen, 1955; Siddiqi, 1970) which comprised 80% of the total stylet bearing nematodes population between the free living nematodes. The soil was sandy loam with pH ranging from 7.8 to 8.0. The following organic amendments were applied at the rate of 500 kg/hectare.
| 1. | Horse manure (C/N ratio 32.6±2.86) |
| 2. | Donkey manure (C/N ratio 34.4±.62) |
Carbofuran was used for comparison at the rate of 15 kg/ha. Organic carbon was estimated by a modified Walkley-Black method (Walkley and Black, 1934) and available nitrogen by method of Subbiah and Asija (1956). All the amendment materials were thoroughly mixed in soil. The treatments were arranged in randomized complete block design and each treatment was replicated four times. Each plot was 1 sq. m in size. The initial (7 days prior to applying amendments) and final (at the time of harvest) populations were determined by Baermann funnel technique. Yield was recorded for each treatment.
Data on density of nematodes were analysed by a factorial analysis of variance (FANOVA) following Zar (1984). As a follow-up of FANOVA Duncan's multiple range test was .employed. The yield data were analysed by analysis of variance (ANOVA).
Results and Discussion
Population densities of nematodes differed significantly with treatments (p<0.001) (Table 1). Population of Helicotylenchus indicus was significantly reduced by the treatments (p at the most 0.05). Greatest reduction was caused by carbofuran followed by donkey manure.
Meloidogyne sp. larval population was also significantly abated by the treatments (p<0.001). Donkey manure caused greatest reduction of Meloidogyne larval density. Similarly, population density of Merlinius brevidens was also significantly (p<0.001) reduced by all the treatments with donkey manure causing the highest reduction in population size. Yield of garlic was significantly elevated in all the treatments (p at the most 0.05). Increase in yield was maximum in carbofuran over the controls (Fig. 1).
The control of nematodes is important as both Merlinius and Helicotylenchus are ectoparasites which feed on root hair and epidermal cells, while Meloidogyrre is an endoparasite which cause damage largely due to disruption of vascular tissue and extensive hypertrophy and hyperplasia of root cells (Siddiqi, 1985). The present work revealed that highest increase in the yield was produced by carbofuran followed by horse manure and donkey manure. It is evident from the foregoing results that animal manures are effective in increasing the yields as compared to control at the same time these amendments reduce the cost of treatment substantially and still be environmentally acceptable with no residual effects.
| Table 1: | Mean nematode population density followed by standard error in different treatments |
| Fig. 1: | Yield in different treatments (CO = Control; HO = Horse manure; DO = Donkey manure; CA = Carbofuran) |