Seasonal suitability of three rubber tree clones to Calacarus heveae (Acari, Eriophyidae)

Abstract

The suitability of rubber tree clones to Calacarus heveae was inferred from the life cycle, reproduction and survivorship of this mite. The assays were performed under controlled conditions with leaflets detached from 6-year-old plants. The development of 20 C. heveae individuals on each of the clones GT 1, PB 235 and RRIM 600 was analysed. This experiment was performed four times during periods when C. heveae was abundant in the field: (P1) November-December 2005, (P2) January-February, (P3) March-April and (P4) May-June 2006. Accordingly, the leaflets used in each assay represented the physiological condition of the host plant during each period. This approach allowed us to evaluate the seasonal suitability of rubber tree clones to C. heveae. We observed seasonal differences in the suitability of rubber tree clones to mite attack. The mites reared on the PB235 had a shorter development period, the highest egg production and highest survivorship. This evidence showed that the PB 235 was the most suitable of those tested. We also observed that the leaflets used in the assays during periods P2 and P3 were the most favourable for the development of C. heveae. This finding emphasises the seasonal suitability of rubber tree leaflets. On the other hand, GT 1 showed higher resistance against C. heveae than did RRIM 600 and PB 235, primarily during the period from November to February. This result indicated that use of the GT 1 clone to control the mite might represent an alternative for growers.

Species Turnover through Time: Colonization and Extinction Dynamics across Metacommunities

“…Similarly, leaf maturation alters leaf photosynthetic properties and associated chemical composition, such as the amount of soluble proteins and the presence of lignin (Lieberei 2007;Miguel et al 2007). These changes are expected to favor some species while disadvantaging others, causing predictable shifts in species composition (Lieberei 2007;Daud et al 2012;Kadow et al 2012). In our system, full leaf maturation occurs after approximately 50 days in natural field conditions (Miguel et al 2007); species changes associated with leaf maturation would be captured in our months 2 and 3 measurements, which is when we observe the first shift toward large numbers of extinctions.…”

“…Rubber trees are deciduous and have synchronized phenological cycles across regions so that all leaves senesce during the dry season (late July or August) and new leaves emerge in September. This annual cycle corresponds to 30-60 generations, depending on the mite species (Feres et al 2010;Daud et al 2012). The combination of seasonal and dispersal dynamics makes the mite system particularly well suited to testing metacommunity processes over time.…”

Population Dynamics of Rubber Tree Mites

“…The low densities of the mite during the senescence period can be evidenced by the population resurgence soon after regrowth of the plants leaves, when these are still young, and gradual increase of the population along the plant development and foliar maturation (Daud & Feres, 2007). The period in which the leaves are more favorable for phytophagous mites development is between January to April (Daud, Feres, & Hernandes, 2012), coinciding with the C. heveae abundance peak, as observed here and by other authors (Daud & Feres, 2007;Feres et al, 2002;Hernandes & Feres, 2006;Vieira et al, 2009). This pattern of increased density of phytophagous mites with the emission of new leaves and peak population at the end of the rainy season were observed for all evaluated clones.…”

Resistência a ácaros de clones de seringueira nas condições do noroeste paulista

“…A presença de fatores de resistência a C. heveae e T. heveae em seringueira tem sido avaliada por alguns autores (Daud e Feres 2007;Ferla e Moraes 2008;Feres et al 2010;Silva et al 2011;Daud et al 2012). Resistência a esses ácaros foi registrada em Mato Grosso para os clones GT 1 e PB 217 (Daud e Feres 2007).…”

“…No Estado de São Paulo, foi registrada resistência nos clones IAC 15, IAC 40, IAC 300, IAN 3156, PB 28/59 e IRCA 111 (Silva et al 2011), além de FX 3899 e IAC 56 (Vieira et al 2013). O clone RRIM 600, de grande importância para a heveicultura, é suscetível às 2 espécies (Vieira e Gomes 1999; Vieira et al 2006;Daud e Feres 2007;Silva et al 2011;Daud et al 2012).…”