Short-term storage conditions for transport and farm delivery of the stink bug Perillus bioculatus for the biological control of the Colorado potato beetle Y. de Ladurantaye1, M. Khelifi1*, C. Cloutier2 and T. A. Coudron3 1Department of Soil Science and Agri-Food Engineering, Universite´ Laval, Quebec, Quebec, G1V0A6 Canada; 2Department of biology, Universite´ Laval, Quebec, Quebec, G1V0A6 Canada; and 3University of Missouri Columbia, USDA, Columbia, USA. *Email: mohamed.khelifi@fsaa.ulaval.ca. de Ladurantaye, Y., Khelifi, M., Cloutier, C. and Coudron, T. A. sur les plants de pomme de terre au printemps. Plusieurs 2010. Short-term storage conditions for transport and farm expe´ riences sur des larves de deuxie` me stade de Perillus delivery of the stink bug Perillus bioculatus for the biological bioculatus ont e´ te´ re´ alise´ es en laboratoire pour examiner les control of the Colorado potato beetle. Canadian Biosystems conditions d’entreposage suivantes: tempe´ rature de l’air, photo- Engineering/Le ge´ nie des biosyste` mes au Canada. 4.1Á4.7. The pe´ riode et dure´ e d’entreposage. Les re´ sultats ont de´ montre´ que most common method of controllingthe Colorado potato beetle les tempe´ ratures d’entreposage entre 9oCet15oC et une (CPB), Leptinotarsa decemlineata (Say), is the application of photope´ riode de (16: 8 h L: N et 0:24 h L: N) n’ont pas affecte´ chemical insecticides. Several alternatives to chemical insecticides de fac¸ on significative la survie et le de´ veloppement apre` s have been proposed, but are in general not yet applicable for l’entreposage des nymphes de Perillus bioculatus et ce pour des current commercial scale production. One of them is augmenta- pe´ riodes d’entreposage de deux a` huit jours. Compare´ a` des tive biological control using a natural insect predator. Consider- pe´ riodes plus courtes, l’entreposage pendant 10 jours a re´ duit la ingthe need of more sustainable agriculture,the objective of this survie d’environ 20%. Le temps de de´ veloppement a` 208C pour study was to develop adequate short-term storage conditions for atteindre le troisie` me stade suite a` l’entreposage n’a pas e´ te´ the second instar nymphs of the predaceous pentatomid, Perillus significativement affecte´ par les conditions expe´ rimentales, bioculatus. This instar has previously been found to be suitable bien que le de´ veloppement ait e´ te´ le´ ge` rement plus rapide a` for release to control eggs and early instars of the CPB in the 158C pendant 10 jours d’entreposage. Comme travaux futurs, il springon potatoes. Many laboratory tests on P. bioculatus sera inte´ ressant d’examiner la dispersion et la performance second instar nymphs have been carried out to investigate the de pre´ dation de Perillus bioculatus suite a` un tel entreposage followingstorageconditions: air temperature, photoperiod, and sous diverses conditions. Mots cle´s: Entreposage, tempe´ rature, period of storage. Results show that storage temperatures within photope´ riode, doryphore de la pomme de terre, insecticides the range of 9 to 15oC and photoperiod (16:8 h L:D and 0:24 h chimiques, alternative, controˆ le biologique, Perillus bioculatus. L:D) did not significantly affect the survival and post-storage development of P. bioculatus nymphs stored for periods of 2 to 8 d. Compared with shorter periods (i.e., less than 8 days), storage for 10 days significantly reduced the survival rate by about 20%. INTRODUCTION Development time to the next instar at 208C followingstorage was not significantly affected by experimental conditions, The Colorado potato beetle (CPB), Leptinotarsa decemli- although development was slightly faster at 158C for 10 days neata (Say) (Coleoptera: Chrysomelidae) is the most of storage. Future studies should investigate the dispersal and important defoliator of potato, Solanum tuberosum (L.), predaceous performance of P. bioculatus followingvarious in Canada (Hare 1980; Boiteau et al. 1992; Howard et al. combinations of storage conditions. Keywords: Storage, 1994), the United-States (Radcliffe et al. 1993), and many temperature, photoperiod, Colorado potato beetle, chemical countries in Europe and Asia (Jolivet 1991). In North insecticides, alternative, biological control, Perillus bioculatus. America, attention has been focused for about 25 yr on Les insecticides chimiques sont couramment utilise´ s pour both the increasingthreat of the CPB resistance to controˆ ler le doryphore de la pomme de terre, Leptinotarsa chemical insecticides and the development of other alter- decemlineata (Say). Plusieurs alternatives a` l’utilisation des natives (Boiteau et al. 1987; Duchesne and Boiteau 1995; insecticides chimiques ont e´ te´ explore´ es, mais demeurent inap- Cloutier et al. 2002). Chemical insecticides have often been plicables a` grande e´ chelle. Parmi ces alternatives, on distingue le efficient in controllingthe CPB on a short-term basis. controle biologique augmentatif utilisant des predateurs natur- ˆ ´ Since the CPB evolved resistance to DDT in the 1950s, els. Dans l’optique d’une agriculture durable, l’objectif de ce travail de recherche e´ tait de de´ terminer les conditions ade´ quates it also acquired resistance to many other chemical d’entreposage des nymphes de deuxie` me stade larvaire du insecticides (Forgash 1981; Martel 1987; Boiteau et al. pre´ dateur Perillus bioculatus. Il a de´ ja` e´ te´ de´ montre´ que ce 1987; Whalon et al. 1993). Currently, resistance to stade larvaire en particulier convient bien a` la distribution au imidacloprid, a recently introduced insecticide that is champ pour controˆ ler les æufs et les petites larves de doryphore widely used to control this insect pest, has been reported Volume 52 2010 CANADIAN BIOSYSTEMS ENGINEERING 4.1 (Mota-Sanchez et al. 2006; Alyokhin et al. 2007). The over would consist of releasing P. bioculatus nymphs as soon use of chemical insecticides can lead to environmental and as springCPB eggmass density can be monitored and health problems for people livingin regionswhere potato used to estimate the potential for damage to potato is intensively cultivated. For decades, biological control crops by first generation resident beetles. In this case, it usingarthropod predators and parasitoids has been would be possible to save on the treatment cost by a investigated as an alternative to chemical insecticides to more precise management of the predators. control CPB populations. To date, most of the developed Compared with eggs and first instars, second instar alternatives have not been efficient enough or difficult to P. bioculatus would be more suitable for mass release apply on a commercial scale. because of their immediate predation potential on small Relatively recent invasive pests, such as the CPB in CPB instars, especially the egg clusters and newly hatched Canada, often have few coevolved natural enemies and larvae, and predator dispersal capabilities in the field, need specific control management. More specific natural which interacts with CPB density through predator hunger predators of CPB eggs and larvae have received and satiation (Lachance and Cloutier 1997; Cloutier particular attention. The two-spotted stink bug, Perillus 1997). On the other hand, eggs and first instar nymphs bioculatus (Fabricius) (Hemiptera: Pentatomidae), native are more fragile, but they do not need to feed, and hence to North America, is amongthe most specialized insect are potentially easier to keep alive duringstorageand predators of the CPB (Knight 1923, 1952; Saint-Cyr and pre-release management. However, their release synchro- Cloutier 1996; Hough-Goldstein et al. 1993; Cloutier nization with early CPB instars would be more difficult et al. 2002) with potential to attack eggs, all larval because of the offset time before developingtheir preda- instars, and even adults of the CPB. Perillus bioculatus tion ability, which is manifest only after moltingto the is predaceous on other chrysomelid larvae, caterpillars, second instar (Hough-Goldstein et al. 1996). Also, they are and other insect herbivores, but it has most frequently possibly more vulnerable to predation and many other been recorded as a predator of the CPB. The biological potential risks. Duringour laboratory experimentation, control of the CPB using P. bioculatus has been efficient we observed that the hatching rate of eggs from mass in small-scale release trials and in cage studies in Europe reared females is variable, even under laboratory condi- (Jermy 1980), Canada (Cloutier et al. 2002), and the United States (Hough-Goldstein and Keil 1991; Biever tions. Thus, more eggs would need to be released to and Chauvin 1992a, 1992b; Hough-Goldstein and compensate potential loss. Hough-Goldstein et al. (1996) Whalen 1993; Poprawski et al. 1997). In Quebec, found that eggs released directly on plants survived Cloutier and Bauduin (1995) and Cloutier and Jean poorly, whereas those placed in a refuge gave as good (1998) experimentally used P. bioculatus nymphs to control of CPB as second instar nymphs that were also control the CPB and observed its predation activity released in a refuge. under a range of temperatures. In augmentative releases, For efficient use of predators for biological control in a ratio of three P. bioculatus second instar nymphs large fields, proper storage and transport techniques are (Fig. 1) to one CPB egg cluster during spring egg laying vital from the production/rearingfacility until their field provided adequate foliage protection. The marked pre- distribution. Transportation over