PLANTS AFFECTED BY EOOT-KNOT. 



11 



affected, whether previously reported or not, the name in the first 

 cohimn is preceded by an asterisk (*). In tlie last column the letters 

 indicate the degree of injury only on those plants observed by the 

 writer, the severest injur}' observed being reported, even though less 

 severe cases have been observed — a = severe injury; b = nematodes 

 abundant, but injury apparently not gi-eat; c = nematodes not abun- 

 dant and no injury observed. It must be imderstood that under 

 different circumstances many plants marked ''a" woidd show little 

 injury, while plants observed as uninjured and noted as ''c" might 

 easily be severely harmed under different conditions. Too much 

 dependence can not, therefore, be laid on this column. In a number 

 of cases the writer has grown in very badly infested fields plants 

 reported by others as susceptible to root-knot, without the slightest 

 signs of infection. Such cases are indicated in the list by a dagger (f). 

 Some of these cases may be of species that are susceptible only imder 

 special conditions, while others may be due to erroneous observation 

 on the part of the first observer or perhaps to the confusion of the 

 bacterial root tubercle with the nematode gall. The former surmise 

 may explain why the writer during a three years' residence in a part 

 of Florida where the disease is very abundant failed to find it in any 

 species of Citrus. Dr. H. J. Webber and Prof. P. H. Rolfs, who have 

 studied plant diseases in Florida for many years, confirm this. Yet 

 Dr. J. C. Neal ^ reports it as occurring on lemon, orange, and bitter- 

 sweet orange, while a similar report is made by Lavergne from Chile.^ 

 In the hst those names added on the authority of Marcinowski ^ 

 are indicated by a double dagger (J) before the name of the plant. 



Table I. — List of plants susceptible to root-knot. 



[An asterisk (*) is used to show those plants which the writer has found affected with root-knot, and a 

 dagger (t) those which he has grown in infested fields without infection, while a doul)le dagger (J) shows 

 the names of susceptible plants added on the authority of Marcinowski. In the last column a=severe 

 injury; b, nematodes abundant, but injury apparently not great; c, nematodes not abundant and no 

 injury observed.] 



Name of plant. 



Name of observer. 



Date of 

 observa- 

 tion. 



Charac- 

 ter of 

 injury. 



*Abelmoschus esculentus (L) Moench. Okra 



*Abroma augusta L. f 



*Abrus precatorins L. Paternoster bean 



*Abutilon avicennae Gaertn. Chinese hemp 



Abutilon sp 



* Acacia dealbata Link 



Acacia, several species from Australia. Wat- 

 tle. 



Achyranthes sp 



Ageratum conyzoides L 



Ageratum sp 



Agropyron repens (L) Beauv. ( Triticum repens). 

 Quack-grass. 



Neal. 



Atkinson. 



C. P. Loimsbury* 



Neal 



Breda de Haan. 

 Zimmermann .. 

 Greef 



1 Neal, 1889. 

 217 



- Lavergne, 1901. 



3 Marcinowski, 1909. 



1889 



1889 



1908 



1889 



1899 



1900-1 



1872 



* In letter. 



a 

 b 

 c 

 b 



