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.
Problems in the use of plant biochemistry for establishing the safety of biological control agents for weeds: TheChondrilla andEchium/heliotropium cases
Demonstration of specificity, on the one hand, of the biological control agents for the weedChondrilla juncea L. [Compositae: Cichoriae] as compared to those for the control of the weedsEchium plantagineum L. andHeliotropium europaeum L. (Tubiflorales:Boraginaceae) represents 2 extremes.In the case ofC. juncea the phytochemical data was insufficiently known to be of value and if it had existed, would have been of little value in demonstrating quarantine safety for certain of the agents. However, in the case of the 2Boraginaceae there is strong evidence that studies based on phytochemical data would have confirmed specificity.RésuméL'étude de la spécificité des agents de lutte biologique contre la mauvaise herbeChondrilla juncea [Composées: Chicoracées] et contre les mauvaises herbesEchium plantagineum etHeliotropium europaeum (Tubiflorales: Boraginées) fait apparaître 2 cas extrêmes.En ce qui concerneChondrilla juncea, les données biochimiques sont de faible valeur pour l'étude de la spécificité en quarantaine de certains de ses antagonistes. En revanche, pour les 2 Boraginacées, il est montré que des études basées sur des données biochimiques auraient confirmé leur spécificité.
A strategy for evaluating the safety of organisms for biological weed control
SUMMARY 
 
A strategy for establishing the specificity and safety of an organism as a biological weed control agent is described. A critical first step is to expose to its attack a small group of plants very closely related and exhibiting morphological and biochemical similarities to the weed. To prevent an erroneous negative result tests are also made on selected cultivated plants, including those closely related to the weed, those of which the associated insects and fungi are little known, those that have evolved apart from or been little exposed to the agent, those attacked by closely related organisms and those already recorded as hosts. 
 
 
 
The circumstances under which the strategy might fail to indicate safety are discussed, i.e. polyphagous organisms attacking plants irregularly distributed throughout many families, organisms highly specific to two alternate hosts, and those attacking two or three phylogenetically widely separated plant groups. The additional crop plant testing, included in the overall strategy to deal with such possible failures, is discussed. 
 
 
 
It is shown that the strategy would have included Sesamum tndicum in the list of plants challenged by the bug Teleonemia scrupulosa in biological testing for control of Lantana camara, thereby forewarning of the attack that was subsequently observed in Africa.