Macadamia farmers are losing almost half of their projected production due to damages by the stink bug if left unchecked early enough. The bug was first detected in Kenya in 1976.
Although stink bugs have several species, the southern green stink bug, Nezara viridula, is the dominant species found in the nut trees. It has piercing sucking mouthparts consisting of a long beak like structure called rostrum. Its life cycle is 65- 70 days and the females can lay up to 260 eggs which are deposited on the underside of the leaves,
Damages
Stink bugs prefer feeding on mature nuts with green husks. Damage caused by stink bug is usually observed after harvesting and processing is being done. The stink bug places its stylet like mouthparts on the nut husk and secretes saliva containing digestive enzymes to soften the husk allowing it to insert it in to the husk and kernel leaving a discolored pit on the kernel surface and also leading to immature drops. Molds and fungi can enter the nut through the infected kernel leading to more loss and undesired quality from harvested nuts.
Control
The southern green stink bug cannot survive on macadamia nuts alone but requires a primary food plant. Weeding hosts plants should be done since the stink bugs reproduce and develop here before feeding on macadamia. To clear the host during land preparation it’s recommended to USE:
CATAPULT 480 SL
Is a non-selective Post emergence herbicide which controls Annual and perennial grasses and broad leaved weeds. Use CATAPULT 480 SL during macadamia Land Preparation to clear all weeds.
Rate of Use: 3.0Litres per Hectare (300ml in 20L)
WEMBE 200 SL
Is a non-selective Post emergence herbicide which controls Annual and perennial grasses and broad leaved weeds. Use WEMBE 200 SL during macadamia Land Preparation to clear all weeds including more resilient or challenging weeds.
Rate of use: 3.0Litres per Hectare (300ml in 20L)
Routine pesticide application is recommended to reduce their population. Products that are systemic and contact in nature come more highly recommended.
For instance;
LEXUS 247 SC
Lexus 247 SC (Thiamethoxam 141g/L + Lambda-cyhalothrin 106g/L) provide both systemic and rapid knockdown control of stink bugs in macadamia trees. Thiamethoxam helps protect the tree by making it less appealing to pests and provides long-lasting control. Lambda-cyhalothrin provides immediate knockdown control upon contact with the stink bugs. It also has a broad spectrum control on Thrips, Aphids, Mealybugs and Whiteflies.
Rate of Use: 200ml per Hectare
KINGCODE ELITE 50 EC
Kingcode elite 50 EC (Lambda-cyhalothrin 15g/L + Acetamiprid 35g/L) provide both contact and systemic control of stink bugs in macadamia trees. Lambda-cyhalothrin delivers immediate knockdown control upon contact with the stink bugs, while acetamiprid provides long-lasting protection as it is taken up by the plant and ingested by the pests.
KINGCODE ELITE 50 EC is a broad spectrum pesticide which controls Aphids, Thrips, Mealybugs and Whiteflies.
Rate of Use: 400ml per Hectare
