Spirotetramat is a modern insecticide from the tetramic acid chemical class, designed for managing various insect pests. It is widely utilized in agricultural and horticultural environments to protect crops and ornamental plants from damaging infestations. It functions as a systemic insecticide, meaning plants absorb it and distribute it throughout their tissues for broad protection. This makes spirotetramat a valuable tool in integrated pest management strategies.
How Spirotetramat Works
Spirotetramat acts as a lipid biosynthesis inhibitor (LBI), interfering with an insect’s ability to produce essential fats. It works by inhibiting acetyl-CoA carboxylase (ACC), an enzyme central to lipid synthesis. This disruption significantly affects the growth, development, and reproduction of target pests. Immature insects, such as nymphs and larvae, are particularly susceptible, experiencing impaired molting and reduced fecundity in adults.
A unique feature of spirotetramat is its “ambimobile” systemicity, allowing it to move in two directions within the plant’s vascular system. Unlike many other systemic insecticides that primarily move upwards through the xylem (water-conducting tissue), spirotetramat can also move downwards through the phloem (sugar-conducting tissue). This dual mobility ensures that all parts of the plant, including new shoots, roots, and even hidden pests, receive protection even if not directly sprayed. Upon absorption, spirotetramat converts into its active enol form, which is then transported throughout the plant, providing effective control.
Commercial and Residential Uses
Spirotetramat is primarily used to control sap-feeding insects, which can cause significant damage to a wide array of crops and plants. It is effective against common pests such as aphids, whiteflies, scale insects, mealybugs, thrips, leafhoppers, and psyllids. This insecticide also shows activity against some spider mites and nematodes, offering a broad spectrum of control for various agricultural challenges.
In commercial agriculture, spirotetramat is applied to major food crops including citrus fruits, apples, pears, grapes, and stone fruits. It is also used on vegetables like tomatoes, cucumbers, peppers, leafy greens, and field crops such as cotton, soybeans, and potatoes. For horticultural and nursery applications, it protects ornamental plants. Spirotetramat is marketed under several common trade names, including Movento® and Kontos®.
Safety and Environmental Profile
Spirotetramat is classified by regulatory agencies such as the U.S. Environmental Protection Agency (EPA) as having low acute toxicity to mammals. While it shows low acute toxicity, it can be irritating to eyes (Toxicity Category II) and is a potential dermal sensitizer, necessitating the use of proper personal protective equipment (PPE) during handling and application. Studies indicate spirotetramat is not likely to be carcinogenic to humans.
The environmental impact of spirotetramat requires careful consideration regarding pollinators. Although acute toxicity tests may show low hazard to adult honey bees, studies suggest potential adverse effects on bee larvae. To minimize risks to bees and other pollinators, applications should be timed to avoid periods of active foraging and bloom.
Spirotetramat is harmful to aquatic invertebrates. The parent compound has a relatively short half-life in soil. However, its primary metabolites, such as spirotetramat-enol, can persist much longer. Total residues, including the parent compound and its major degradates, show significantly higher persistence in both soil and aquatic environments. These persistence characteristics are important factors in its regulated use to mitigate potential environmental accumulation.