Comparative Susceptibility of Two Banana Cultivars to Banana Bunchy Top Virus Under Laboratory and Field Environments

Abstract

Field and laboratory experiments were carried out on the island of Oahu, HI, to compare the susceptibility of the two most commonly grown banana (Musa sp.) cultivars in the state ('Dwarf Brazilian' or Santa Catarina [locally known as dwarf apple] and 'Williams') to the aphid-borne Banana bunchy top virus (genus Babuvirus, family Nanoviridae, BBTV). Several morphological and physiological features of the two cultivars were monitored to determine whether the banana aphid, Pentalonia nigronervosa Coquerel (Hemiptera: Aphididae), transmits BBTV to both cultivars at a similar rate; and whether after successful inoculation, does each cultivar respond similarly to viral infection. Results from the laboratory experiment showed that a similar percentage of both cultivars were infected with BBTV by aphid vectors (> 90% for both cultivars). However, field results showed a significantly lower percentage of dwarf apple (39%) infected with BBTV compared with Williams (79%). We also found that all physiological and morphological features measured (i.e., plant height, leaf area, canopy, chlorophyll level, and moisture content) for both cultivars were impacted similarly by BBTV. The incubation period, or the time between plant infection and initial appearance of disease symptoms, was similar for both cultivars. Results also showed that BBTV transmission efficiency was lower in the field than in the laboratory, despite that more aphids per plant were used for field than laboratory inoculation tests. The results highlight the potential use of less susceptible cultivars to help manage BBTV and the importance of screening banana varieties in the field to determine their response to vectors and associated diseases.

Genetic structure and diversity of the Banana bunchy top virus population on Sumatra Island, Indonesia

“…As for the reason underlying this phenomenon, BBTV may adapt banana varieties that include a B genotype. Previous studies have shown that some banana varieties including the B genotype have resistance for BBTV (Hooks et al 2009;Furuya et al 2012). Perhaps, since there may have been some resistant bananas in our sample, the viruses infecting banana varieties including the B type genotype may have greater diversity than those infecting banana varieties including only the A genotype.…”

Disease progression of vector-mediated Grapevine leafroll-associated virus 3 infection of mature plants under commercial vineyard conditions

“…Other studies that have compared laboratory and field results have had mixed findings. For example, Hooks et al (2009) also found a higher transmission efficiency of Banana bunchy top virus by aphids based on laboratory experiments compared to commercial agricultural conditions. Another study that included transmission of Cucumber mosaic virus and Zucchini yellow mosaic virus by multiple aphid species found that the relative transmission rates between field and laboratory conditions depended both on aphid and virus species (Castle et al 1992).…”

“…Hooks et al 2009), and there is considerable variation in estimates of transmission efficiency of GLRaV-3 among laboratory studies (Almeida et al 2013). The laboratory and field studies were consistent with each other in that there was no effect of caging the insect vectors on the recipient test vines on virus transmission.…”

Population Distribution and Density of Pentalonia nigronervosa (Hemiptera: Aphididae) Within Banana Mats: Influence of Plant Age and Height on Sampling and Management

“…Although sampling was similar to that described in Robson et al (2006), each leaf position and all plant parts from the bottom to the top of the canopy was inspected for aphids; and sample sites extended beyond the island of Oahu. Aphids are believed to be concentrated in the leaf axis between the petiole and pseudostem (Young and Wright 2005), also referred to as the "throat" of the pseudostem (Hooks et al 2009b). Therefore, the petioles were peeled back and the area within the leaf axes inspected for aphids.…”