Record of rust diseases of the Chrysanthemum, Gladiolus and Limonio in the Cochabamba Valley, Bolivia

Flower production is an important economic activity in the Cochabamba Valley, Bolivia. Species and varieties of Roses (Rosa sp-), Chrysanthemums (Chrysantemum sp.), Carnations (Dianthus carophyllus), Gladiolus (Gladiolus communis), Saticias (Limonium sp.), Liliums (Liliums sp.,) etc. are grown. Rusts affect a variety of crops, including flowers. The aim of this study, was identify the rust diseases that is affecting to three important flower species. Stems and leaves of samples with characteristic rust symptoms of smallholder farmer parcels were collected between 2016 and 2018 of the Chrysantemum grandiflorum, G. communis and Limonium sp. Based on morphometric studies the causal agent of rust diseases was identify as the first record to Puccinia horiana on chrysanthemum, Uromyces transversalis on Gladiolus and Uromyces limonii on Limonio in the Cochabamba Valley, Bolivia.


INTRODUCTION
The Bolivian Inter Andean Valleys (2000 -3000 meters above sea level), due to its favorable weather, soil conditions and water availability, are suitable for the vegetables and flowers production. Currently, in the Central and Lower Cochabamba Valley of department, Bolivia, flower production is an important economic activity. Species and varieties of Roses (Rosa sp-), Chrysanthemums (Chrysantemum sp.), Carnations (Dianthus carophyllus), Gladiolus (Gladiolus communis), Saticias (Limonium sp.), Liliums (Liliums sp.,) etc. are grown for the local market and a small part for export. Smallholder farmers mostly grown in the "open field" and for export are grown under cover [1].
One of the limiting factors in the flowers production are the fungal diseases. Fungi, like rust disease, are destructive. Globally they are considered one of the most serious threats to agriculture [2]. Rusts affect a variety of crops, including flowers. According to Buritica et al, [3] in Colombia, rusts affect different flowers species and some such as Gladiolus rust is considered of plant quarantine in Europe and the United States [4]. At present rust affects several flowers species, they have widespread distribution and cause production losses in the Cochabamba Valley. However, there are only isolated reports of rust disease for Bolivia. Otazu et al. in the "Plant diseases in Bolivia" reported only to carnation rust caused by Uromyces caryophyllinus [5]. The aim of this study, was identify the rust diseases that is affecting to three flower species by morphological details of urediniospores and teliospores collected from natural infections in the farmers' field in the Cochabamba Valley, Bolivia.

Chrysanthemum rust
The pustules were formed mostly on the lower side of the leaves ( Figure 1A,B,C). On the leaves or stems were not found other spore state of the rust fungi. According to Hernandez et al. Spermogonia, aecia and uredinia unknown [6]. Telia hypophyllous, compact, yellowish, 2-3 mm diameter, often clustered in irregular pattern. The teliospores were thin walled, bicelled, pedicellate, pale yellow, oblong to oblong-clavate, 30-50 × 10-16 µm, slightly constricted at the septum, smooth; pedicel hyaline persistent, up to 45 µm long ( Figure 1D). According to Hernandez et al [4] and based on this morphometric studies the causal agent is Puccinia horiana Henn.

Limonium rust
The pustules are formed on the leaves and stems, are yellowish and reddish-brown and irregular form ( Figure 1I,J). Uredinia amphigenous, pulverulent and orange, mm, sori at first covered by the blistered epidermis which finally burst (Fig. 1K). Uredionospores variable in form and size, ellipsoide or globose and minutely echinulate. Telia amphigenous similar to uredinia, black-brown ( Figure 1K). Teliospores (22-28 μm length and 20-24 μm in wide) oblong to ellipsoid, unicellular, rarely ovate, color yellow-orange to light brown. the wall is light brown, smooth and thick or thicker at the top. The pedicel is hyaline (50 μm) ( Figure 1L). Spermagonia and Aecial phase not was observed and according Garcia-Hernandez et al. [7] this spore state are unknown. Therefore, based on this description and according to Garcia-Hernandez et al. [2] the causal agent is Uromyces limonii (D.C.) Lev. 1849.

CONCLUSION
These are the first record of the following rust disease affecting several species flowers, P. horiana on chrysanthemum, U. transversalis on Gladiolus, U. limonii on Limonium sp.in the Cochabamba Valley, Bolivia.