7 questions on the use of drones for the application of Trichogramma parasitoids

The recent Grow Asia Digital Learning Series and ASEAN FAW Action Plan webinar on Drones and Digital IPM on Thursday 9 December 2021 featured a presentation by Dr Lian-Sheng Zang from Guizhou University on the Novel Use of Drones for Releasing Trichogramma Parasitoids against Agricultural Pests in China.

Dr Zang answered many questions from the audience and in this blog we share his responses. One of the videos related to his work that couldn't be played in the workshop is below and shows the use of drones for releasing Trichogramma against soybean pod borer. The other video can be found on our programme page along with the webinar recording and copy of presentations.

Q1: In general, how many hectares would you need to apply Trichogramma in this way, for this method to be cost-effective?

In my experience, at least 20ha is needed because a one-time departure of the drone can control about 20ha with releasing the Trichogramma. You can also manually release the carriers - for this situation, one person could control pests with the carriers for around 40ha in about 8 hours. In this situation, we evenly release 45 carriers per ha, placing each carrier at about 10 m intervals.

Q2: Can you use any pesticides in conjunction with Trichogramma application – or does it need to be one or the other?

In northeastern China, on most occasions, only the corn borer, rice stem borer and soybean pod borers need to be controlled. For these pests, only releasing the Trichogramma is enough to control them. For some diseases, conventional chemicals also need to be used. When used carefully, they can be used in conjunction with the Trichogramma.