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Australian All About Almonds Almonds www.australianalmonds.com.au Carob moth in almonds David Madge, Cathy Taylor and David Williams, Department of Economic Development, Jobs, Transport and Resources, Victoria A large part of the carob moth’s life cycle Introduction occurs inside almond mummies - nuts that Identification of carob moth Carob moth Apomyelois (=Ectomyelois) remain on trees after harvest, and it seems Table 1 contains a summary of the different ceratoniae is a pest of numerous tree likely that its increased populations and life stages of carob moth. See the fact crops around the world, including damage to almonds seen in recent years sheet ‘Carob moth: Monitoring guidelines’ almonds. In recent years carob moth began with increases in the numbers of for more complete descriptions. has caused increasing concern for the mummies in orchards. Mummies often Australian almond industry. The larval develop as a result of hull rot, a fungal Biology & behaviour stage (caterpillar) of carob moth feeds on disease that develops on almonds once almond kernels, making them unsuitable the hulls have split and is favoured by Carob moth is in the moth family Pyralidae, for sale as whole kernels for human warm, wet conditions. Such conditions members of which are commonly referred consumption, and possibly increasing the occurred across our major almond growing to as ‘snout moths’ because of the snout- risk of fungal infection. The presence of districts soon after hull split in 2007 and like appearance of their mouthparts. Pyralid insect-damaged kernels can also reduce 2011. At the same time, the number of moths include Indian meal moth Plodia the quality grading of whole batches of bearing trees in the industry was growing interpunctella, a widespread major pest kernels, resulting in significant economic rapidly, doubling between 2004 and 2007 of stored foods, and navel orange worm loss. and more than doubling again to 2011. (NOW) Amyelois transitella, the main pest The exponential growth in nut production of almonds in USA. Carob moth is considered to have combined with favourable conditions for Like most insects, the development and originated in the Mediterranean area hull rot is likely to have resulted in very behaviour of carob moth is dictated by but it is now widely distributed across large increases in mummy numbers across temperature. Eggs will not develop below many countries. In California, carob moth the industry. became the only serious insect pest of about 16°C, larvae require temperatures dates after its appearance in the Coachella above 9.5-12.5°C depending on diet, and Valley date-growing region in 1982. It about 12.5°C is also the minimum for pupal has not yet become a noticeable pest in development. Moth flight is unlikely at California’s commercial almond crops in temperatures below 15°C. the Central Valley to the north, possibly The moths tend to stay still during the day due to the geographical separation of and fly, mate and lay eggs between dusk the two regions and to the stringent and dawn. Each female can lay up to 200 management controls already in place for eggs, with most being laid within the first its relative, the navel orange worm. six days after the moth’s emergence from its pupal case. The moths survive typically An old pest of new for about one week, but up to two weeks importance under ideal conditions. Plants that carob moth infests and that Carob moth has been recorded in almonds are likely to be found in almond districts in Australia since the 1960s but appears in Australia include pistachio, Chinese fan to have been considered a real problem palm, date, carob, honey locust, black only sporadically. During the unusually wet locust, chestnut, walnut, fig, guava, olive, summer of 2010/11, some growers noted pomegranate, quince, loquat, apple, high levels of kernel damage from carob apricot, citrus and grape (dried fruit moth leading up to harvest, indicating that remaining on vines). under the right conditions this moth can become a serious economic pest. Figure 1: A Carob moth larva and damaged kernel. All About Almonds - Fact Sheet Egg New larva Mature larva Pre pupa Pupa Adult 0.7mm long. 1mm long. Up to 15mm long. Up to 15mm long. About 12mm long. 8-12mm long. White when laid, Typically pink. Typically pink. Typically pink. Stops Dark ridge and Grey with 13-20mm pink when mature. Actively feeding. Actively feeding. feeding & spins a silk double row of ‘teeth’ wingspan and wavy cocoon for pupation. on back. pattern. Table 1: Life stages of carob moth. aspect of its NOW management program Both insecticides target the eggs and larvae Carob moth has been found to prefer and the same approach is likely to benefit of moth pests including carob moth and are laying eggs on mouldy fruits and nuts. This the Australian industry. The Californian reported to have minimal disruptive impact includes almond mummies and immature industry recommends that mummy numbers on beneficial species such as predators and almonds that are infected with anthracnose, be reduced to a maximum of two per tree parasites. otherwise it only lays onto current-season to obtain significant benefits in the way almonds once the hull has split. of reduced kernel damage from NOW. For more details on the APVMA permits, contact the ABA, and before using any In many instances, carob moth infests Indications are that a similar threshold will pesticide, read and follow the label almonds only between the hull and shell, apply for carob moth. instructions. with no kernel damage occurring. In Effective mummy management involves Sunraysia, as little as 2% and up to 30% not just removal of mummies from trees, of infested nuts have been found to have Biological control but also destruction of those nuts, by flail damaged kernels. Globally, 38 species of parasitic wasps have mowing for example, to destroy any carob been recorded to attack carob moth, along moth they contain. Life cycle in almonds with several parasitic flies and predatory beetles and bugs. The European earwig The typical life-cycle of carob moth in Harvest management Forficula auricularia is also a predator of almonds in Australia is described in Table Infestation and damage levels within the carob moth and is present in large numbers 2. Data from moth trapping and modelling current-season crop increase significantly, in many almond orchards. Several species indicate that usually three full generations the longer that crop is exposed to egg- of parasitic wasps have been observed of carob moth develop each season. The laying by carob moths. This means that on carob moth in almonds in Australia, spring generation takes about eleven weeks kernel damage can be minimised by including Trichogramma carverae, one to develop from eggs to adults, while harvesting the new crop as soon as possible of the species reared commercially for warmer temperatures help the summer once it is mature, and fumigating or management of moth pests in other crops generation develop in eight weeks. In processing it without delay. (Figure 2 & 3). Biological control may make some orchards and seasons, sporadic flights a useful contribution to the management of can be detected as late as early June, Insecticide carob moth in Australian almonds but it is probably in response to a series of warm yet to be fully explored. days. These flights may suggest the start At the time of writing this fact sheet two of a fourth generation of moth emergence insecticide options were available for carob Current research which is then cut short by a return to low moth management in almonds through temperatures. permits from the Australian Pesticides and Pheromone-based mating disruption was Veterinary Medicines Authority (APVMA), developed to manage carob moth in arranged by the Almond Board of Australia dates in USA and has been the subject of Management options (ABA). recent research in almonds in Australia. Mating disruption aims to restrict the Orchard hygiene An emergency use permit allows the development of damaging populations application of Altacor® (DuPont™; 350 g/ The importance of mummy nuts to carob of pests by interfering with the ability of kg chlorantraniliprole) at hull-split and a moth development in almond orchards males and females to locate each other, minor use permit allows Prodigy™ (Dow cannot be overstated. Neither can the thereby reducing the prevalence of mating AgroSciences; 240 g/L Methoxyfenozide) potential value of mummy management, and production of viable eggs. While this to be used between egg hatch in the first both as a control strategy for this pest and a approach has shown some promise in generation of carob moth (September) and risk-reduction exercise against carpophilus almonds, further work is required to achieve hull-split. beetle, diseases such as hull-rot, and the necessary results in improved kernel contamination of the current-season quality and to determine its economic crop at harvest. In California, the almond viability. industry uses mummy reduction as a key ~ 2 ~ Almond Board of Australia Inc. P + 61 8 8582 2055 9 William Street, PO Box 2246 l Berri South Australia 5343 E [email protected] l W www.australianalmonds.com.au All About Almonds - Fact Sheet Late Winter Larvae begin to pupate inside mummy nuts on the trees. Spring As temperatures rise, larvae and pupae complete their development and start to emerge as moths. The moths fly and mate at night and females start laying eggs on mummy nuts. All eggs of this generation will be laid on mummy nuts. Emergence and egg-laying by this generation of moths continues to the end of spring. Summer Eggs laid in early spring have developed into moths which now begin to emerge and mate.