Estimating the level of fruit scarring by citrus thrips from temperature conditions prior to the end of bloom

Pezothrips kellyanus (Thysanoptera: Thripidae), nueva plaga en cítricos; comportamiento de sus poblaciones, muestreo y enemigos naturales

“…It has been related with air temperatures in the case of S. citri. Cool weather during early March and warm weather during bloom were associated with higher percentages of scarred fruit (Schweizer and Morse, 1997). Interannual variation has also been observed in KCT .…”

“…According to Schweizer and Morse (1997), cool weather during early March and warm weather during citrus blooming are associated with high levels of fruit scarring caused by S. citri. They argue that cold weather in early March may ensure timely hatching of diapausing eggs and could also prolong the period during which the young citrus leaves are suitable for S. citri feeding and survival during the first larval generation.…”

“…They argue that cold weather in early March may ensure timely hatching of diapausing eggs and could also prolong the period during which the young citrus leaves are suitable for S. citri feeding and survival during the first larval generation. But S. citri develops only on soft tissue of young fruit, tender leaves and shoots of citrus and overwinters in the egg stage inside the leaf tissue (Horton, 1918;Schweizer and Morse, 1997), whereas KCT develops primarily on citrus flowers, and to a lesser extent on small fruitlets and mature fruits (Baker et al, 2002;. Moreover, KCT overwinters on mature fruits or alternative hosts.…”

“…Similarly, the percentage of KCT immatures on developing fruits remained high (> 50%) in 2008 and 2009, but not in 2010. The synchronization was also important regarding fruit scarring caused by S. citri in citrus in California (Schweizer and Morse, 1997).…”

“…Como hemos visto, P. kellyanus se desarrolla principalmente en flores de cítricos y, en menor medida, en frutitos en desarrollo y en frutos maduros. Por otro lado, S. citri se desarrolla en tejidos jóvenes como hojas y brotes tiernos, no en flores y frutos maduros, e hiberna en estado de huevo en el tejido de las hojas (Horton, 1918;Schweizer y Morse, 1997a). Este comportamiento probablemente refleje el diferente contexto evolutivo de las especies comparadas: P. kellyanus es una especie polífaga que se ha convertido en plaga seria de cítricos recientemente (Mound y Jackman, 1998), mientras que S. citri ataca principalmente a cítricos y ha sido considerada plaga seria de cítricos desde los inicios del siglo XX (Ebeling, 1959) y está probablemente más adaptada a la fisiología del árbol cítrico.…”