Lettuce varieties with high resistance (HR) to the Impatiens necrotic spot virus (INSV)
INSV Defense lettuce varieties protect against the Impatiens necrotic spot virus (INSV). This virus is transmitted by the western flower thrips. INSV in lettuce causes characteristic patterns of chlorosis and necrosis on the inner leaves of the plant as well as significant stunting. INSV is a serious problem in the Salinas Valley, the key lettuce-producing area in the USA. A 2020 survey of 1,350 fields in the Salinas Valley revealed an average crop loss of 33% and a 100% loss in some fields. INSV Defense is a unique resistance in Rijk Zwaan’s Defense line.
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Why growers choose INSV Defense
Lettuce varieties with INSV Defense have a high resistance (HR) against INSV. This means that this resistance strongly restricts the growth and development of the specified pest under normal pest pressure in comparison to susceptible varieties. Highly resistant varieties may, however, exhibit some symptoms or damage under heavy pest pressure.
Advantages of INSV Defense
- High resistance to Impatiens necrotic spot virus (INSV)
- Healthy crop
- Secure production
Lettuce varieties with INSV Defense
Two Romaine lettuce varieties with INSV Defense are currently commercially available: FARMIN RZ and JAMMIN RZ. Both these Romaine varieties have positive agronomical characteristics and are well adapted to US market requirements. Other lettuce varieties are already being developed. All INSV-resistant lettuce varieties will be identifiable by their names (ending in ‘in’) and will display the INSV logo.
What is INSV?
INSV a member of the genus Orthotospovirus and is closely related to the Tomato spotted wilt virus (TSWV). Transmission of INSV between crops has been attributed predominantly to the western flower thrips (Frankliniella occidentalis). The virus replicates within the insect vector and is transmitted to new plants by adult thrips as they feed on epidermal and mesophyll cells of susceptible host plants.
Trials show a clear difference
Over the past two years, the US team in Salinas and various dealers ran a total of 49 field trials. These trials confirmed that two selected varieties had high resistance (HR). “There was an amazing difference between the susceptible variety and the two resistant varieties: JAMMIN RZ and FARMIN RZ.