MICROBIOLOGICAL CONTROL OF CARPOCORIS FUSCISPINUS (HEMIPTERA: PENTATOMIDAE), A PEST OF ONION AND LEEK SEED CROPS

Abstract

Any agricultural production requires the prior production of seeds, carried out by specialized companies, which own in-depth knowledge of seed crops as well as of their pathogens and pests. These pathogens and pests often remain unknown to the agricultural world. They are very little studied and control strategies do not exist. The present study is typical of such a situation: Zollinger Bio, an organic seeds producer, regularly deals with seed crops health problems. Over the last years, the production of seeds of onion (Allium cepa) and leek (Allium ampeloprasum var. porrum) has been reduced by 50% by a bug, morphologically and genetically identified as Carpocoris fuscispinus. Their piercing-sucking mouthparts allow these insects to empty the maturing seeds. Carpocoris fuscispinus, a native bug in Europe, has never been considered as a pest, although observed once as a cereal pest in Iran. The pest has already caused damage during flowering making the use of insecticides not possible, because of their harmful effect on pollinating insects. Entomophagous fungi could be an alternative. Two fungal isolates, Beauveria bassiana UASWS 1427 and Paecilomyces fumosoroseus UASWS 1457, were tested against C. fuscispinus. The experimental units consisted of five bugs in a box with water and food (leek flower, spelled crop seeds). The mortality increased quickly between day four and day eight and reached 100% adults for B. bassiana and 90% for P. fumosoroseus at day eight. Similar results were obtained on larvae. These results are promising of a possible microbiological control against C. fuscispinus.