Life histories and host specificities of theEchium flea beetlesLongitarsus echii andL. Aeneus [Col. Chrysomelidae]
Two halticine flea beetles,Longitarsus echiiKoch andLongitarsus aeneusKutsch, occurring on the boraginaceous plantEchium plantagineum L. in the western Mediterranean region are potential biological control agents in Australia where the plant has become a weed (Paterson's curse). The adults of both species feed by making “shot holes” in the leaves. The larvae of both species attack the roots ofEchium, those ofL. echii feeding more centrally in the root than those ofL. aeneus which attack the outer cortex and rootlets. Both species are univoltine. The host restrictions of both flea beetles as adults and as larvae were tested using the criteria already established for theEchium leaf minerDialectica scalariellaZeller (Wapshere & Kirk, 1977). This testing established that it would be safe to introduce the 2 insects into Australia for the biological control ofE. plantagineum and they are now under quarantine.RésuméDeux altises,Longitarsus echiiKoch etLongitarsus aeneusKutsch, vivant surEchium plantagineum L. dans l'ouest de la région méditerranéenne, sont des agents de contrôles biologiques potentiels de cette adventice en Australie. Les adultes des 2 espèces creusent des trous dans les feuilles et leurs larves attaquent les racines de la plante. Les larves deL. echii se nourrissent plus de la partie centrale de la racine, alors que celles deL. aeneus préfèrent le cortex extérieur et les radicelles. Les 2 espèces ont une génération par an. La spécificité d'hôte des 2 espèces, tant adultes que larves, a été étudiée selon les critères déjà établis pourDialectica scalariellaZeller (Wapshere & Kirk, 1977). Ces essais ont confirmé que l'introduction des 2 insectes en Australie pour la lutte biologique contreEchium plantagineum serait sans danger, et cette introduction a eu lieu récemment.
The host range and impact of Bikasha collaris (Coleoptera: Chrysomelidae), a promising candidate agent for biological control of Chinese tallow, Triadica sebifera (Euphorbiaceae) in the United States
Native to China, the Chinese tallow, Triadica sebifera (Euphorbiaceae) is an aggressive woody invader in the southeastern United States. The flea beetle, Bikasha collaris (Coleoptera: Chrysomelidae), is a common herbivore attacking this plant in China. To evaluate its potential as a biological control agent the host specificity and impact were studied in China. The potential host range of B. collaris was evaluated on 68 plant species in 20 families through no-choice and choice tests. Adults only survived and fed on plants from the genus Triadica while larvae only developed successfully on T. sebifera in no-choice tests. Under choice conditions, adults showed a distinct preference for T. sebifera over other Triadica species. The impact of the above- and belowground herbivory on the growth of T. sebifera was evaluated in a common garden.B. collaris could reduce stem height, total biomass, number of leaves and stem diameter at a density of 10 individuals per plant. Above- and belowground herbivory had similar effects on plant growth parameters. The results of this study suggested that B. collaris is a potential biological control agent of T. sebifera though further tests on native North American species are needed.
Color image based sorter for separating red and white wheat
A simple imaging system was developed to inspect and sort wheat samples and other grains at moderate feed-rates (30 kernels/s or 3.5 kg wheat/h). A single camera captured color images of three sides of each kernel by using mirrors, and the images were processed using a personal computer (PC). Real time image acquisition and processing was enabled on an ordinary PC under Windows XP operating system using the IEEE 1394 data transfer protocol, DirectX application software, and dual-core computer processor. Image acquisition and transfer to the PC required approximately 17 ms per kernel, and an additional 1.5 ms was required for image processing. After classification, the computer could output a signal from the parallel port to activate an air valve to divert (sort) kernels into a secondary container. Hard red and hard white wheat kernels were used in this study to test and demonstrate sorter capability. Simple image statistics and histograms were used as features. Discriminant analysis was performed with one, two, or three features to demonstrate classification improvements with increased numbers of features. The sorter was able to separate hard red kernels from hard white kernels with 95 to 99% accuracy, depending on the wheat varieties, feed-rate, and number of classification features. The system is an economical and useful instrument for sorting wheat and other grains with high accuracy.