Au cours de deux essais en champ, cinquante-deux especes et varietes de Musa ont ete testees pour... more Au cours de deux essais en champ, cinquante-deux especes et varietes de Musa ont ete testees pour leur sensibilite envers les nematodes Radopholus similis, Hoplolaimus pararobustus et Meloidogyne incognita. Le groupe des bananiers plantains AAB presente la plus grande sensibilite tant envers R. similis que H. pararobustus. Les types AAA et ABB marquent une tendance vers une moindre sensibilite a R. similis, quelques varietes etant meme proches de la resistance. H. pararobustus et M. incognita sont moins representes que R. similis et dans leur cas les differences varietales de sensibilite sont moins marquees
The effect of juvenile cereal cyst nematodes (Heterodera avenae) on the root growth of oat and ba... more The effect of juvenile cereal cyst nematodes (Heterodera avenae) on the root growth of oat and barley seedlings was tested in three pot experiments. Invasion by juveniles hindered the extension of the seminal root axes of both cereals; after invasion, axes took 2–3 days to attain normal rates of extension. This response was found in susceptible and resistant cultivars. When oats and barley were exposed to continued invasion over 9 days, barley produced a larger root system than oats and was less stunted by nematode invasion. The density of nematodes per unit of root was less in barley than in oats. The effects on root growth were similar to reported responses of roots to mechanical damage.
SUMMARYNewly germinated seedlings of susceptible cultivars of oats, wheat, barley and rye were in... more SUMMARYNewly germinated seedlings of susceptible cultivars of oats, wheat, barley and rye were inoculated with second‐stage juveniles of Heterodera avenae in pots of sand. Subsequent examination showed oat root tips to be more commonly invaded, and by a greater range of nematode numbers than the other cereals.A comparison of oats and barley showed that lower nematode numbers in barley were not due to a higher emigration from barley; invasion, establishment and emigration by nematodes all being greater in oats. Second‐stage juveniles were more likely to migrate prior to establishment in barley than in oats.
In the Lake Victoria region of East Africa bananas are a starchy staple of major importance. Whil... more In the Lake Victoria region of East Africa bananas are a starchy staple of major importance. Whilst concerns over banana cultivation in the region have been expressed for well over 50 years, over the last 30 years these have grown more serious, with data suggesting that banana yields have halved in some areas since the 1970s. Historical and survey evidence demonstrate that the banana burrowing nematode, Radopholus similis, and the associated 'black-head toppling disease' were absent from the region prior to the 1960s. It is suggested that the introduction of R. similis to Uganda and its subsequent rapid spread in many of the banana growing areas of the Lake Victoria region is a major component of the severe production difficulties the crop is presently facing. Evidence for the continuing spread of R. similis in East and Central Africa and the implications of this are discussed.
Au cours de deux essais en champ, cinquante-deux especes et varietes de Musa ont ete testees pour... more Au cours de deux essais en champ, cinquante-deux especes et varietes de Musa ont ete testees pour leur sensibilite envers les nematodes Radopholus similis, Hoplolaimus pararobustus et Meloidogyne incognita. Le groupe des bananiers plantains AAB presente la plus grande sensibilite tant envers R. similis que H. pararobustus. Les types AAA et ABB marquent une tendance vers une moindre sensibilite a R. similis, quelques varietes etant meme proches de la resistance. H. pararobustus et M. incognita sont moins representes que R. similis et dans leur cas les differences varietales de sensibilite sont moins marquees
The effect of juvenile cereal cyst nematodes (Heterodera avenae) on the root growth of oat and ba... more The effect of juvenile cereal cyst nematodes (Heterodera avenae) on the root growth of oat and barley seedlings was tested in three pot experiments. Invasion by juveniles hindered the extension of the seminal root axes of both cereals; after invasion, axes took 2–3 days to attain normal rates of extension. This response was found in susceptible and resistant cultivars. When oats and barley were exposed to continued invasion over 9 days, barley produced a larger root system than oats and was less stunted by nematode invasion. The density of nematodes per unit of root was less in barley than in oats. The effects on root growth were similar to reported responses of roots to mechanical damage.
SUMMARYNewly germinated seedlings of susceptible cultivars of oats, wheat, barley and rye were in... more SUMMARYNewly germinated seedlings of susceptible cultivars of oats, wheat, barley and rye were inoculated with second‐stage juveniles of Heterodera avenae in pots of sand. Subsequent examination showed oat root tips to be more commonly invaded, and by a greater range of nematode numbers than the other cereals.A comparison of oats and barley showed that lower nematode numbers in barley were not due to a higher emigration from barley; invasion, establishment and emigration by nematodes all being greater in oats. Second‐stage juveniles were more likely to migrate prior to establishment in barley than in oats.
In the Lake Victoria region of East Africa bananas are a starchy staple of major importance. Whil... more In the Lake Victoria region of East Africa bananas are a starchy staple of major importance. Whilst concerns over banana cultivation in the region have been expressed for well over 50 years, over the last 30 years these have grown more serious, with data suggesting that banana yields have halved in some areas since the 1970s. Historical and survey evidence demonstrate that the banana burrowing nematode, Radopholus similis, and the associated 'black-head toppling disease' were absent from the region prior to the 1960s. It is suggested that the introduction of R. similis to Uganda and its subsequent rapid spread in many of the banana growing areas of the Lake Victoria region is a major component of the severe production difficulties the crop is presently facing. Evidence for the continuing spread of R. similis in East and Central Africa and the implications of this are discussed.
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