Laeveld Agrochem focuses on Tuta absoluta
Tuta absoluta has been a constant thorn in the side of many growers across South Africa, costing them millions of Rands worth of revenue. One of the crops affected is tomatoes. In the Brits-area, Anna van der Merwe, from Laeveld Agrochem, Brits was supported by a team of experts that undertook to design a spray programme to control the Tuta absoluta to the advantage of the grower. The past season they achieved success with this programme amongst many growers in Gauteng. Hygrotech is honoured to have permission and support from Anna to publish this programme in the Hygrotech Forum, as it can benefit everybody in the tomato industry. We are also very proud that we could contribute in a small way and have one of our flagship products playing an integral part in the programme. Nu Film P® is synonymous with Hygrotech the past 50 years and once again this product has delivered on what it was designed to do.
Leafminers that attack solanaceous crops
(note: limitless variations of damage symptoms may be encountered)
Tuta absoluta has caused serious damage and economic losses since 2016, particularly on tomatoes. The plague has since also been observed on other crops of the Solanaceae like brinjals, potatoes and tobacco. The insect is a moth and resorts under the order: Lepidoptera. After the moth has laid her eggs, it takes 3 to 5 days to hatch. The wandering phase of the newly hatched larva? takes 10 – 30 minutes before they start to gorge through the cuticula to tunnel into the leaf. Fruit and stems are also prone for the same damage. The larva stage is usually completed in 8 -14 days, whilst all the larva-instars enjoy the security of a leaf cuticula or fruit mesocarp. This impedes the control of Tuta absoluta.
It is further important to take note of the specific process of nutrition of the insect, as the time of exposure to any chemical product on the leaf surface is very short. As a consequence, it is therefore essential to deposit as much as possible of any registered Tuta-chemical product for as long as possible and on the biggest surface area of the plant possible.
The use of a wetting-, sticking- and spreading product like Nu Film P® is recommended for this purpose in conjunction with an insecticide. Nu Film P® also protects the insecticide against UV degradation and enhances rain fastness. Lengthened control is therefore obtained and the effectiveness of all the so-called ‘worm’ remedies is promoted.
Anti Resistane Management Programme for the control of Tuta Absoluta in tomatoes
(2nd Edition, February 2022)
The following images (presentation) is an output of the Tuta absoluta task team of the South African Department of Agriculture, Forestry and Fisheries.
Fully grown larvae
Leaf mines
Tomato leafminer
Written by: Henry van der Voort & Anna van der Merwe, BSc Agric (Hons) Horticulture.
