Author
|
Submitted to: University of Georgia Research Report
Publication Type: Experiment Station Publication Acceptance Date: 6/1/2005 Publication Date: 7/1/2005 Citation: Davis, R.F. 2005. Effect of the southern root-knot nematode on watermelon yield. In: Kelly, W.T. , Langston, D.R. (eds.). Georgia Vegetable Research-Extension Report 2004. Tifton, GA: University of Georgia. p. 60-61. Interpretive Summary: Watermelon is an excellent host for the southern root-knot nematode, but the level of damage caused by the nematode to watermelon is not known. This study evaluated the effect of the southern root-knot nematode on the number and weight of individual melons, and the total weight of all melons, by comparing yields in methyl bromide-fumigated and non-fumigated plots. Each plot had six Cooperstown seedless watermelon plants and two Companion watermelon plants as pollinators. Mature fruit were collected during two harvests. After the second harvest, roots were rated for galling on a 0-10 scale. Fumigated plots had very low nematode pressure during the study, whereas non-fumigated plots had high nematode pressure: the mean root gall rating was 1.0 for fumigated plots and 5.3 for non-fumigated plots. Thirty percent fewer fruit were collected from non-fumigated plots than from fumigated plots during the first harvest. The total weight of fruit also was reduced by 30%, but the mean weight per fruit was not affected. The number and weight of fruit from the second harvest did not differ between fumigated and non-fumigated plots. When the two harvests were combined, the number of fruit was 19% lower and the weight of fruit was 23% lower in non-fumigated plots, but the mean weight per fruit was not affected. Meloidogyne incognita reduced the yield of watermelon by reducing the number of fruit produced and delaying the maturity of those fruit, but the weight of individual fruits was not reduced. This documents that M. incognita is a significant pathogen of watermelon, and that nematode management is necessary. Technical Abstract: Watermelon (Citrullus lanatus) is an excellent host for the southern root-knot nematode (Meloidogyne incognita), but the level of damage caused by M. incognita to watermelon is not known. This study evaluated the effect of M. incognita race 1 on the number and weight of individual melons, and the total weight of all melons, by comparing yields in methyl bromide-fumigated (200 lbs a.i./A) and non-fumigated plots. Each plot had six Cooperstown seedless watermelon plants and two Companion watermelon plants as pollinators. Mature fruit were collected during two harvests. After the second harvest, roots were rated for galling on a 0-10 scale. Fumigated plots had very low nematode pressure during the study, whereas non-fumigated plots had high nematode pressure: the mean root gall rating was 1.0 for fumigated plots and 5.3 for non-fumigated plots. Thirty percent fewer fruit were collected from non-fumigated plots than from fumigated plots during the first harvest. The total weight of fruit also was reduced by 30%, but the mean weight per fruit was not affected. The number and weight of fruit from the second harvest did not differ between fumigated and non-fumigated plots. When the two harvests were combined, the number of fruit was 19% lower and the weight of fruit was 23% lower in non-fumigated plots, but the mean weight per fruit was not affected. Meloidogyne incognita reduced the yield of watermelon by reducing the number of fruit produced and delaying the maturity of those fruit, but the weight of individual fruits was not reduced. This documents that M. incognita is a significant pathogen of watermelon, and that nematode management is necessary. |
