Management of Onion Thrips (Thrips tabaci) in Organic Onion Production Using Multiple IPM Tactics

Abstract

Onion thrips (Thrips tabaci Lindeman) is a major pest in organic onion production and effective integrated pest management strategies are lacking. Our objective was to evaluate combinations of semi-glossy (“Rossa di Milano” and B5336AxB5351C) and waxy (“Bradley”) onion cultivars with reflective mulch, with or without biopesticides (spinosad + neem oil tank mix), to manage T. tabaci in organic onion production. Thrips densities were assessed weekly and bulbs graded and weighed at harvest. Onions sprayed with spinosad + neem oil had fewer T. tabaci (adults: 74% (2019); larvae: 40% (2018), 84% (2019) and produced higher yields (13% (2018), 23% (2019)) than onions that were unsprayed, regardless of mulch type or onion cultivar. “Rossa di Milano” had relatively fewer adult and larval thrips populations compared with “Bradley” (21% (2018), 32% (2019)) and B5336AxB5351C. However, “Rossa di Milano” had the lowest marketable yield in both years. Reflective mulch reduced densities on certain dates in both years compared to white mulch, but the largest and most consistent reduction only occurred in 2019. Reflective mulch had no impact on bulb yield. While spinosad + neem oil reduced thrips numbers and increased yield alone, none of the treatment combinations were effective at suppressing populations of thrips. Future T. tabaci management in organic onions will require optimization of the available effective biopesticides.

Integrated Management of Onion Thrips on Onion, Mecha District, Ethiopia

“…Thrips infestation was significantly higher in unprotected plots than in protected plots. Onions sprayed with neem oil had fewer T. tabaci and produced higher yields than onions unsprayed, regardless of the onion cultivar (Iglesias et al, 2021). Botanicals possessed considerable differences in mortality rate and the efficacy of botanical showed that neem seed powder was significantly superior in efficacy (Tesfaye et al, 2021).…”

Efficacy of entomopathogenic fungi, nematodes and spinetoram combinations for integrated management of Thrips tabaci

“…Currently management of onion thrips is accomplished with the application of conventional insecticides. However, due to the unique characteristics of this pest, such as short generation time, cryptic behaviors and rapid reproduction, multiple applications of insecticides are required 8,9 . These repeated applications have various drawbacks, such as resistance development, residual and nontarget effects, cost, and hazards to human and livestock health 10 .…”

“…However, due to the unique characteristics of this pest, such as short generation time, cryptic behaviors and rapid reproduction, multiple applications of insecticides are required. 8,9 These repeated applications have various drawbacks, such as resistance development, residual and nontarget effects, cost, and hazards to human and livestock health. 10 It is therefore essential to develop and use insecticides with novel modes of action that efficiently reduce the thrips populations while reducing hazardous effects on nontarget organisms and the environment.…”

“…[12][13][14][15] These two qualities (longer residual and new mode of action) have resulted in interest in its potential use for management of a variety of insect pests, especially thrips, dipterans and lepidopterans. Spinetoram provides efficient control against thrips 9,[16][17][18] on onion and other allium species, and has been extensively used on several crops. For example, spinetoram has been suggested for the control of T. hawaiiensis in mango and banana plantations.…”

Assessment of Genetic Variability in Onion against Purple Leaf Blotch Disease under Field Conditions and its Management

“…Numerous strategies, including the application of fungicides and plant extracts have been tested against A.porri ( Jhala et al, 2017a;Yadav et al, 2017;Younas et al, 2021). Among all strategies, some are not economically applicable for the farmers because of their high cost whereas others have direct or indirect deteriorating and degrading effect on human beings and environment (Iglesias et al, 2021). Perfect method to overcome the maladies is the use of resistant onion genotypes.…”