Pink bollworm (Pectinophora gossypiella) is one of the most destructive pests of cotton in many areas of the world, including in India, China, Brazil and the western USA. In its adult, or moth, stage, the pink bollworm lays its eggs on cotton bolls. The eggs hatch into larvae that eat the cotton seeds and damage and discolour the fibre. The National Cotton Council of the USA estimates that the pink bollworm costs American cotton producers more than US$32 million each year in control and yield losses.
Oxitec Pink Bollworm (OX1138)
In a sterile moth release control programme, it is critical to be able to accurately determine whether moths caught in traps are released sterile ones or fertile wild ones.
In the current SIT programme, released moths are marked with dye administered in the feed, but there is a concern that this is not reliable enough, so the industry is interested in alternative markers.
The Oxitec Pink Bollworm strain OX1138 contains a fluorescent marker that glows red when viewed under certain filters. Because it is integrated into the insects’ DNA, the red marker can always be detected during the insect’s lifetime and it is inherited if offspring are produced. The marker can also be detected by analysing DNA in the laboratory, guaranteeing complete accuracy. The strain is otherwise identical to that used in the current SIT programme and is sterilised by irradiation in exactly the same way. The strain offers completely reliable monitoring to existing sterile insect programmes.
OX1138 has been evaluated in 3 years of open release trials by the USDA-APHIS-Plant Protection and Quarantine (PPQ)-Center for Plant Health Science and Technology (CPHST) Laboratory in Phoenix, Arizona.
APHIS Biotechnology Regulatory Services has performed two Environmental Assessments (EA) and declared “findings of no significant impact” (FONSI) on field releases of Genetically Engineered Pink Bollworm. The USDA has conducted an Environmental Impact Assessment (EIS) addressing the impact of the area–wide use of genetically engineered pink bollworm in the context of the existing SIT programme and in 2009, declared that their use was not merely acceptable but was the “the environmentally preferable option”.
Performance in evaluation
CPHST has evaluated the strain for 3 years in open field trials and in mass-rearing trials in the mass-rearing facility. Over this time, more than 20 million genetically modified moths have been released in the USA. The red marker performs consistently well. It is still brightly visible after 2 weeks in the field or 4 months in the lab. The field and rearing performance of the strain is comparable to that of the current strain.
Oxitec Pink Bollworm (OX3402)
An early RIDL pink bollworm prototype has been tested in cage trials by USDA APHIS Plant Protection and Quarantine, Center for Plant Health Science and Technology (CPHST).
The Oxitec Pink Bollworm has now completed thorough contained trials and lab tests in its product optimisation stage. The new improved homozygous strain, OX3402, is now available for demonstration in the open field, and will soon be ready for full commercial application.