An Overview of Effective Thrips management in Ornamentals

Signs and symptoms of thrips infestation.

Thrips are tiny, slender insects that feed on plants by rasping and sucking out the contents of plant cells. Thrips are often found on flowers, fruits, and leaves. Common symptoms of thrips on ornamental plants include discoloration of petals, distortion of leaves and flowers, and stunted growth.  Silvering or stippling on the leaves, as well as black fecal droppings left behind by the thrips are clear signs of infestation. Yellow or blue sticky traps in monitoring thrips populations is a noble practice. Proactive measures to control them before they cause significant damage. 

There are over 6,000 species of thrips found in a wide range of habitats. Each species of thrips may have specific feeding preferences and behaviors, making them a challenging pest to manage. Among the most common species of thrips include the Western Flower Thrips (Frankliniella occidentalis), the Onion Thrips (Thrips tabaci), and the Chilli Thrips (Scirtothrips dorsalis) which infect wide range of ornamental plants, including roses, chrysanthemums, dahlias, gladioli, carnations, hypericum, alstroemeria and various types of flowering plants. 

Effects of Persistent thrips infection.

Thrips indirectly contribute to the spread of diseases by feeding on plant tissues creating wounds that serve as entry points for pathogens. They contribute to infection of botrytis in roses by feeding on petals and soft plant tissue creating wounds that can serve as entry points for botrytis spores. This interaction between thrips and botrytis highlights the importance of integrated pest management strategies that address both thrips and botrytis control. Monitoring and managing thrips populations can help reduce the risk of botrytis outbreaks in sensitive varieties.

Epidermal damages caused by thrips also leads to reduction in photosynthetic rate impacting on crop productivity.

Due to their rapid reproductive rate and ability to hide in small crevices they are difficult to reach and eliminate effectively. Additionally, their ability to feed on a wide range of plants make them a persistent pest in ornamental crops. This calls for proper thripicide application timing and coverage for effective control.

Thrips may develop resistance to pesticides, including metabolic resistance, target-site resistance, and behavioral resistance. Repeated exposure to the same pesticide mode of action can make them less susceptible to the pesticide. Metabolic resistance occurs when thrips detoxify pesticide more effectively, making it less toxic to them. Target-site resistance involves changes in the thrips' genetic makeup that make the pesticide less effective at its intended target site within the insect's body. Behavioral resistance can occur when thrips change their behavior to avoid contact with the pesticide or develop mechanisms to reduce its impact. It is important to monitor thrips populations and adjust pest management strategies accordingly.

Weather factor in Thrips Management.

Temperature plays a crucial role in the development and multiplication of thrips. Thrips multiplication is influenced by the external environment. Warmer temperatures generally accelerate thrips activities and reproduction rates. In optimal temperatures (around 25-30°C), thrips tend to have shorter life cycles, with faster egg hatching, larval development, and adult emergence. Low temperatures can slow down their development and reproduction by creating less favorable conditions for their survival. Wind impacts thrips populations by aiding their movement and dispersal allowing them to spread to new areas and infest crops. Overall, understanding and monitoring of local weather conditions and thrips flare up help in implementing effective thrips management strategies. Monitoring weather patterns and adjusting control measures accordingly is important in managing thrips infestations in greenhouse and outdoor ornamentals.

Thrips predators.

The common commercial predators used in ornamental crops for thrips control include Orius insidiosus (Minute Pirate Bug), Amblyseius cucumeris (Predatory Mite), Neoseiulus cucumeris (Predatory Mite), Chrysoperla carnea (Green Lacewing), and Aphidius colemani (Parasitic Wasp). These predators target thrips at various life stages, aiding in reducing thrips populations. They are part of an integrated pest management strategy for sustainable and environmentally friendly thrips control. It's emphasized to adhere to the guidance of pest control experts and suppliers when using biological control agents.

Role of adjuvants in thrips management.

Sugar additives can both positively and negatively affect thripicide effectiveness, as sugar can lure thrips to the pesticide, increasing ingestion and overall efficacy, but the concentration and type of sugar used should be carefully considered. Adjuvants improve thripicide penetration into concealed areas of plants, ensuring better coverage and contact with thrips. Adjuvants improves spray coverage which is paramount to maximizing thrips exposure to the pesticide.  Additionally, adjuvants prevent wash off during rains in outdoor crops like hypericum, eryngiums, ensuring prolonged efficacy of contact pesticides against thrips.

In summary, the careful use of adjuvants significantly improves the effectiveness of thripicide strategies, resulting in better control, reduced crop damage, and fewer interceptions. However, it's important to choose adjuvants judiciously, following label instructions to ensure compatibility and maximize their benefits. For more information on use of adjuvants and thrips management visit our Expert Centre.

Action of pesticides on thrips

Growers faces several challenges when it comes to deciding on of thrips solutions. Secondary standards impact on growers’ choices which are increasingly getting limited every year. This situation is worsened by the limited modes of action available to growers. Due to these challenges its advisable for growers to understand the working mechanism of every thrips solution. 

Pesticides target thrips through various mechanisms. Contact pesticides, such as pyrethrins and pyrethroids, work by directly contacting thrips, by ingestion or disrupting their feeding behavior. Systemic pesticides are absorbed by plants and affect thrips when they feed on the treated plant tissues. These pesticides disrupt thrips' physiological processes when ingested during feeding. 

Additionally, insect growth regulators (IGRs) can control thrips by interfering with their growth and development. Insect growth regulators like Match^® infer trans ovarian effect to female thrips leading to laying of sterile eggs. However, the effectiveness of different insect IGRs on thrips may vary based on the specific product. It is also recommended to rotate between different modes of action (MoA) of pesticides and use integrated pest management strategies for effective control of thrips. Proper management of thrips populations is important in preventing the spread of diseases on ornamental crops and maintaining the overall health, production and beauty of the flowers.

To help growers be on top of thrips control Syngenta Ornamentals is introducing a new insecticide for ornamental growers. The new brand, Mainspring^®, is unique, fast acting, friendly, reliable solution for thrips problem to ornamental growers irrespective of prevailing conditions.