Andrew Creek and Dr Jianhua Mo (NSW DPI): March 2018
The galls currently seen on trees are caused by wasps that emerged in spring 2017. Autumn chemical control trials conducted by the citrus gall wasp project team reveal that certain chemical control treatments applied in autumn can significantly reduce the number of wasps emerging about six months later in the spring. This is especially important for those varieties that cannot be treated in the spring because of late hanging fruit (e.g. Valencia) or blocks with heavy infestations that need a “double knock”.
Samurai and imidacloprid trial results summary
- Soil application of Samurai® at 8 g per tree applied to Valencia after harvest in mid-March reduced gall wasp emergence by 50% compared to untreated control (Figure 1).
- Imidacloprid (e.g. Confidor®) was not effective against gall wasp in the autumn application, even after two seasons of application at three different sites.
Note: Both Samurai® and Confidor Guard® have extensive withholding periods. Always follow label recommendations.
Movento® trial results summary
- Trials over the last two seasons have shown that Movento® applied in March or April reduced the emergence of adult wasps in the following spring by over 60% (Figure 2).
- Late February and March applications provided good control in Chislett navels.
- Spring applications of Movento® did not control gall wasp.
Note: Movento® is registered for scale and mealy bug in citrus, it is not registered for citrus gall wasp. Always follow label recommendations.
NSW DPI project team contacts:
- Dr Jianhua Mo 02 6951 2537 (Yanco)
- Andrew Creek 0428 934 952 (Yanco)
- Steven Falivene 0427 208 611 (Dareton)