# Susceptibility of Cooking Herbs to Stored-Product Moths

## TL;DR

This study examines how dried cooking herbs resist or support the growth of two types of stored-product moths, finding that some herbs prevent pest development while others allow it but more slowly.

## Contribution

The study identifies specific herbs that inhibit or delay the growth of stored-product moths, offering insights into natural pest resistance in stored foods.

## Key findings

- Tarragon, sage, savory, oregano, and thyme inhibited the growth of both moth species.
- Chervil, chives, coriander, and dill supported development but took longer than a standard diet.
- Idaea inquinata could develop on more herbs than Plodia interpunctella.

## Abstract

Like other stored foods, dried cooking herbs can be damaged by various insect pests, despite containing secondary metabolites that may be toxic to insects. These pests can affect the amount and quality of food, and the effects of infestation often do not become apparent until it has already taken hold. This study investigates the ability of two Lepidoptera pests—one polyphagous, Plodia interpunctella, and one selective, Idaea inquinata—to feed on eleven dried herbs frequently used in cooking. Tarragon, sage, savory, oregano, and thyme were found to inhibit the growth of both species, indicating the presence of chemical components that restrict larval growth or survival. Furthermore, both species can complete development on chervil, chives, coriander, and dill. However, it took longer than on a standard diet, suggesting a nutritional deficiency.

Although herbs can contain several secondary metabolites potentially harmful to insects, dried herbs, like all stored foods, can be damaged by various insect pests. These pests have the potential to diminish both the quantity and the quality of food, and the consequences of infestation often only become noticeable once the pest has already become established. This study investigates the ability of two Lepidoptera pests, one polyphagous, Plodia interpunctella, and one selective, Idaea inquinata, to complete the postembryonic development on eleven dried herbs commonly used in cooking: dill (Anethum graveolens L.), basil (Ocimum basilicum L.), chervil (Anthriscus cerefolium (L.) Hoffm.), coriander (Coriandrum sativum L.), tarragon (Artemisia dracunculus L.), chives (Allium schoenoprasum L.), oregano (Origanum vulgare L.), parsley (Petroselinum crispum (Mill.) Fuss), sage (Salvia officinalis L.), savory (Satureja hortensis L.), and thyme (Thymus vulgaris L.). The results show that tarragon, sage, savory, oregano and thyme did not allow growth of either species, suggesting the presence of chemical compounds that limit larval growth or survival. In addition, the time required for both species to complete development was longer than that obtained on a standard diet, suggesting that the nutritional requirements and water content of the herbs are not as optimal as those of the standard diet. To conclude, I. inquinata could develop on basil, chervil, chives, coriander, dill, and parsley, while P. interpunctella could develop only on chervil, chives, coriander, and dill.