TY  - JOUR
JF  - Acarologia
T1  - Occurrence and biological performance of Tetranychus urticae (Acari: Tetranychidae) on rice seedlings
VL  - 66
IS  - Suppl
SP  - 275
EP  - 275
PY  - 2026
SN  - 0044-586X
SN  - 2107-7207
PB  - Les Amis d'Acarologia
AU  - Kettlin, Ruffatto
AU  - Raul Antonio, Sperotto
AU  - Liana, Johann
UR  - https://doi.org/10.24349/mwri-j145
DO  - 10.24349/mwri-j145
DA  - 2026-07-20
ET  - 2026-07-20
KW  - Mite
KW  - Behavior
KW  - Monoculture
KW  - Agriculture
KW  - Occurrence
AB  - The two-spotted spider mite, Tetranychus urticae Koch, is a highly polyphagous species and one of the agricultural pests worldwide, infesting more than 1,100 plant species, many of economic importance. In Brazil, it occurs in at least 36 cultivated plants, including soybean (Glycine max L.), one of the most important crops in Rio Grande do Sul. Rice (Oryza sativa L.) has economic relevance in the region and is frequently cultivated near soybean, which may favor the dispersal of pests such as T. urticae between crops. However, records of T. urticae on rice are scarce. This study aimed to confirm the occurrence of T. urticae on rice seedlings and evaluate its development, oviposition, and feeding preference. The mites used in this study were obtained from rice plants (cultivar IRGA 424-RI) naturally infested in a germination room of rice and bean (Phaseolus vulgaris L.) at the Universidade do Vale do Taquari – Univates, in Lajeado, RS, Brazil. Bean plants were naturally infested with the mite, whose individuals moved to the rice seedlings. Mites on rice plants were collected and mounted on slides for taxonomic identification based on dichotomous keys and morphological characteristics, including dorsal striae pattern, pretarsus structure, and male aedeagus morphology, using a microscope (Zeiss Axio Imager M2). Developmental stages were monitored from the egg stage (n=60) under controlled laboratory conditions and recorded through photographs. Body measurements of adult females reared on rice and bean leaves were compared (n=10 for each plant species). Females of known age had oviposition evaluated over six days, in the presence and absence of males. Feeding preference assays were conducted using dual-choice tests with rice and bean leaves. Mites collected from rice leaves were identified as T. urticae and completed the life cycle on rice leaves, confirming this crop as a viable host. Females reared on rice showed significantly smaller body size (p<0.0001) than those reared on bean. Oviposition rates were significantly reduced on rice (p<0.01), regardless of male presence. Feeding preference tests showed that mites from rice and bean plants significantly preferred bean leaves over rice leaves. These results indicate that although rice allows mite development, it is a less suitable host than legumes. This study provides the first biological characterization of T. urticae on the rice cultivar IRGA 424-RI in Brazil and highlights the importance of monitoring this mite in rice-producing areas, especially where soybean is cultivated nearby.
ER -