Samples of black pepper root with the presence of galls from the most southern region of the State of Bahia, Brazil, were characterized biochemically and morphologically using three criteria: i) observation of the anterior region of the males; ii) analysis of female perineal configuration and iii) polyacrylamide gel electrophoresis technique.
- nematological survey
- root-knot nematode
Black pepper (
Despite the growing production, pipericulture faces serious phytosanitary problems, mainly due to the occurrence of soil pathogens such as fungi and root-knot nematodes,
Considering the importance that root-knot nematodes represent and the lack of consistent information about the distribution and occurrence of these pathogens in black pepper, this work aimed to characterize, biochemically and morphologically, the gall nematode species associated with black pepper plantations in the most southern region of the State of Bahia, Brazil.
The study was carried out at Fazenda Conjunto Bom Jardim, located in the municipality of Itabela, in the extreme south of Bahia, Brazil, on a property composed of 10 ha grown with black pepper (latitude 16 ° 44 ‘45’ ‘S and longitude 39 ° 28’ 58 ‘’ W), altitude of 120 m at sea level, with four years of age and 3.70 x 1.65 m spacing. Three areas were selected, each consisting of 1 ha, two of them with cv. Kottanadan Roxa and the other with cv. Bragantina. The samples were collected from 0 to 30 cm deep, in the rhizosphere region, giving preference to the collection of radicellae from weakened plants (Fig. 1).
After zig-zag walking in each area, 10 subsamples were collected that made up 1 composite sample for each area.
The samples were packed in plastic bags, duly identified, and sent to the Laboratory of Nematology at the Research Center for Plant Protection and Animal Health, of the Instituto Biológico, in Campinas, SP, for extraction and identification of phytoparasitic nematodes.
The nematodes were extracted from 10g of roots using the method of Coolen and D´Herde (1972) and the quantification was performed in Peters slide.
The identification of the
Thirty-five females were used in the isoenzymatic identification (esterase) considering five females per sample, totaling seven samples. Five females were also used for identification by the perineal configuration and five males for observation of the anterior region of the nematode.
For this study formal consent is not required.
Black pepper plants parasitized by gall nematodes generally become chlorotic, with severe leaf yellowing, defoliation and reduction in chlorophyll content, which affects vegetative development, resulting in significant reduction in yield and even death (Freire & Monteiro, 1978; Ferraz & Lordello, 1989; Mohandas & Ramana, 1991). Some of these symptoms, such as yellowing, defoliation and roots with numerous galls were observed in the plants analyzed in our study.
Studying the anterior region of the males and analyzing the perineal configuration of the females, the presence of
We observed females with perineal pattern rounded to ovoid, with thin to thick streaks. Low dorsal arch, flattened, with smooth or slightly wavy streaks, slightly bent towards the tail tip on the lateral line; usually forming shoulders on the lateral portion of the arch. The dorsal and ventral striations are usually at an angle on the lateral lines; distinct lateral field, slightly irregular. In males, the labial region was continuous with the rest of the body, smooth, labial disc more or less rounded, slightly elevated above the level of the medial lips. Long distance from the orifice of the dorsal esophageal gland to the base of the stylet.
The analysis of polyacrylamide gel electrophoresis also revealed a characteristic profile of
The numbers of second stage juveniles (J2) + eggs extracted from black pepper roots are shown in Table 1. Both cultivars showed a high number of
Number of second stage juveniles (J2) and eggs of
The first study that showed the presence of
In Brazil, reports involving the black pepper pathosystem x
In Brazil, the only report of
Considering that the success of any nematode management strategy depends, initially, on the knowledge of the species present in the areas where it is desired to reduce the population of these pathogens, the information obtained in the present work may be useful in the development and adoption of appropriate techniques for the management of parasitic nematodes of black pepper.
The species of gall nematode associated with black pepper cultivation in the extreme south of the State of Bahia is
Number of second stage juveniles (J2) and eggs of Meloidogyne arenaria obtained in 10 g of root from black pepper cv. Kottanadan roxa and Bragantina in cultivation areas in the extreme south of the state of Bahia, BA.