Spatial and Temporal Distribution of Iris yellow spot virus and Thrips in Colorado Onion Fields

Abstract

Iris yellow spot virus and its onion thrips vector (Thrips tabaci) are yield limiting pests of onion in the western United States. This two-year project investigated the relationship of iris yellow spot to thrips populations, soil properties, and grower management practices in six onion fields during 2005 and 2006 in Colorado. Thrips density (average number of thrips per plant per day) was negatively associated with soil pH (r = -0.61). The incidence of iris yellow spot at harvest was positively associated with organic matter, zinc, potassium, percent sodium, percent hydrogen, copper, iron, and soil pH. Thrips-days had a clear non-linear association with disease incidence at harvest. Onion plant population was positively associated with levels of iron, phosphorus, potassium, and zinc; and negatively associated with calcium, salts, percent potassium, and cation exchange capacity (CEC). Marketable (medium or larger sized bulbs) yield was negatively associated with phosphorus and percent potassium, and positively associated with salts, calcium, and CEC. Results from this project could contribute to the development of a risk index to predict potential risk from Iris yellow spot virus and its onion thrips vector. Accepted for publication 6 July 2010. Published 20 August 2010.

Recent Advances in Onion Genetic Improvement

“…Mechanical inoculation of IYSV has proven ineffective in causin onions as the transmission rate is low [77,78]. Germplasm evaluation for IYS re has relied upon field evaluations [51,55,56,[79][80][81][82][83][84][85][86]. One problem with field evalu ensuring that IYSV is present in the field and equally distributed throughout t Since mechanical inoculation is not effective in reliably producing IYS, disease ment is dependent upon thrips transmission throughout the field.…”

“…When 75 different plant introduction (PI) accessions were evaluated, plants of PIs 239633 and 546192 exhibited fewer IYS disease symptoms than plants of most accessions [53]. Other germplasm evaluations for IYS susceptibility have been conducted without a similar field layout [83][84][85][86][87].…”

“…The field layout mentioned has also been used to make individual plant selections for reduced symptom expression and to evaluate the progress achieved for reduced disease from these selections [56,80,81,86]. When selections were made from PI accessions, selected breeding lines, NMSU 10-575-1, 10-577-1, and 10-582-1, exhibited less IYS severity than their original accessions [56].…”

Iris yellow spot virus (Tospovirus: Bunyaviridae): from obscurity to research priority

“…As a result, various production practices that could influence disease outbreaks have been identified. Based on these observations, a risk index to estimate and predict the likelihood of disease outbreaks has been developed and is being validated (Schwartz et al ., ).…”

Current status and distribution of major RNA viruses infecting onion and garlic crops in Punjab, Pakistan

“…In Allium crops, accumulation of RNA viruses in bulb used for propagation and polyphagous insect vector transmission has cardinal role in low production (Das et al, 2021;Baudry et al, 2021). Potyviruses and carlaviruses disseminated through aphid (Myzus persicae) non-persistently and favorable environmental conditions enhance the transmission rate (Perotto et al, 2014;Jayasinghe et al, 2021), while tospoviruses transmitted in persistent manner through thrips (Thrips tabaci) (Jenser & Szénási 2004;Schwartz et al, 2010;Birithia et al, 2013), and allexiviruses transmitted by (Aceria tulipae) a mite semipersistently (Dhall, 2015;Jangra et al, 2021;Mansouri et al, 2021b). Previous reports based on serological detection followed by RT-PCR showed that these viruses occurred endemically causing mixed infection demonstrated by Sevik & Akcura, (2013).…”