Hyperspectral application for early diagnosis of American foulbrood disease in the honeybee (Apis mellifera L.) larvae

Abstract

Non-destructive methods are of utmost importance for early diagnosis of American foulbrood (AFB) disease in honeybees’ larvae. This study discusses the potential application of spectroradiometric techniques for spectral discrimination of AFB disease in honeybees. AFB is a honeybees’ brood fully destructive bacterial disease caused by the spore forming bacterium; Paenibacillus larvae (P. larvae). It is important to detect the disease early as routine apiary administration and interchange of coloney components could spread it easily to healthy ones. Hyperspectral measurements of honeybee larval samples from 11 colonies were taken in range (350–2500 nm). The two spectral bands, Red and the Short-Wave Infrared (SWIR2), were of the promising results for differentiation between healthy and the different degree of honeybees’ larval infection. Correlation coefficient between Red and SWIR2 spectral reflectance data indicates that SWIR2 is the best spectral band to be used for discriminating between healthy and infected honeybee larvae. Confirmation of AFB was carried out by both cultivating smears of suspected larvae on agar plates and KAT-PCR technique for bacterial DNA confirmation. Both cultivation and PCR results agreed with hyperspectral results indicating that 6 colonies were of high loads of P. larvae, 2 of moderate bacterial loads and 1 was weak. Only 2 colonies appeared free from bacteria. Data analysed, discriminatory signatures the diseased samples in their various pathological stages. this research is an attempt to determine the feasibility of early diagnosis of AFB disease in honeybee brood through the application of hyperspectral technology.