All About Almonds - Fact Sheet
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Australian Almonds All About www.australianalmonds.com.au Almonds Carob moth in almonds: Monitoring guidelines David Madge, Cathy Taylor and David Williams, Department of Economic Development, Jobs, Transport and Resources, Victoria to pink as they mature. The larvae are Mummified nuts on trees are a critical Introduction typically pale to dark pink and range from food and breeding resource for carob Carob moth Apomyelois (=Ectomyelois) about 1 mm long when newly hatched to moth. Local experience so far indicates ceratoniae attacks numerous tree crops 15-20mm long when fully mature (Figure 1c, that carob moth is more likely to be at worldwide and causes economic damage d). The top side of carob moth pupae are very low levels or absent in orchards with by feeding on fruits or nuts, contaminating marked with a dark ridge and double row of very few or no nut mummies present over them with frass (excreta) and rendering ‘teeth’ (Figure 1e) which help to distinguish winter. This relationship may not hold true if them unfit for human consumption. It has them from the otherwise similar pupae of heavily-infested orchards are nearby. If nut been considered a serious pest of almonds Indian meal moth. mummies are present in significant numbers in Australia in recent years. throughout the orchard (i.e. at least several Adult carob moths (Figure 1f) are a medium- per tree) but no carob moth infestations To make informed decisions regarding the dark grey colour with a wingspan of about are found, it is possible that carob moth treatment of orchards against carob moth, 13-20mm. A wavy pattern crosses the wings is absent from that orchard. In contrast, producers need some basic information about one third of the way down their where a reasonably high proportion of the regarding its presence and population length. This pattern helps to differentiate mummies are infested, there is potential levels. To help producers monitor carob carob moth from other similar moths. for a significant carob moth population to moth effectively, this fact sheet describes In almonds, carob moths survive winter as develop and damage the new season’s some simple monitoring techniques. larvae and pupae inside mummified nuts crop. The information will be revised as more hanging on trees. The pupae complete their local knowledge is developed. The development during late winter/early spring, development and behaviour of carob moth Monitoring and mature moths begin to emerge soon in almonds is addressed in a separate fact after. The purpose of monitoring for carob sheet. moth is to determine whether it is present After mating, female moths lay their eggs in a particular orchard and whether its Description & lifecycle on mummified nuts hanging on trees. This population level is concerning enough to continues until hull split in the new crop, warrant management action. Carob moth eggs (Figure 1a, b) are about after which some eggs will be laid on new 0.7 mm long, white when fresh, changing crop nuts (Figure 2a). The following approaches to monitoring may be useful for producers to develop a better understanding of the pest. Figure 1a: Newly laid carob moth eggs are white (above) and Figure 1c: Recently hatched larvae are about 1 mm long Figure 1e: Pupal cases are about 10 mm long and carry a dark turn pink when mature (Figure 1b below). (above) and grow to 15-20 mm (Figure 1d below). ridge and double row of ‘teeth’. Figure 1b Figure 1d Figure 1f: Adult carob moths are grey, about 8-12 mm long with wings folded and have a 13-20 mm wing span and a wavy pattern across their wings (arrowed). All About Almonds - Fact Sheet Table 1: Nut assessments for carob moth in almonds Timing Nut type Sample type Look for Purpose of inspection At least 100 intact Larvae and pupae between Determine if CM is present and assist decision making Late winter Mummies nuts from across hull & shell and in kernel on the need for control action in the new season the block Monitor population development and impacts of At least 100 intact Fresh eggs anywhere, larvae adverse weather and natural enemies, and assist Prior to hull split Mummies nuts from across and pupae between hull and decision making on the need for control action at hull the block shell and in kernel split At least 100 intact Fresh eggs anywhere, larvae Assess effectiveness of any control actions applied Just prior to harvest New crop nuts from across and pupae between hull and earlier and assist decision making on the need for the block shell and in kernel post-harvest control action (e.g.fumigation) inspections may be done with the naked eye Nut inspections in the orchard. A regime of nut assessments to monitor carob moth infestation levels is summarised From early spring onwards, eggs and small in Table 1. The distribution of carob moth larvae may be present. A 10x hand lens will infestation within an orchard block can be then be required for in-field inspections, patchy, so it is important to collect nuts from or the nuts may be taken to a convenient as many different locations across the block location for inspection with a hand lens or as practical. dissection microscope. As carob moth is very unlikely to lay eggs Infested mummified nuts and new crop nuts Figure 3b: Tent-shaped delta traps (above) are easy to use may have carob moth present only between on new crop nuts until hull split, there is little the hull and shell, or only in the kernel, or value in assessing new nuts until that time. both. As would be expected, the more nuts By late winter, the infestation of mummified examined, the more accurate the assessment nuts is obvious because of the presence of will be. A record should be kept of the frass, silken webbing and large pink larvae number of nuts inspected and the number or pupae (Figure 2b). For this reason, winter infested with carob moth in each orchard block. Moth trapping Moth traps provide an easy and useful guide Figure 3c: The sticky base can be removed for easy counting of moths and replacement of the lure to relative population levels of carob moth at different times of the season and between tweezers - they can be affected by orchard blocks. Female carob moths produce high temperatures, direct sunshine and a sex pheromone to attract males for mating contaminants such as nicotine and other and a synthetic mimic of that pheromone chemicals is available as ‘lures’ - small rubber plugs • Place lures on their side near the centre impregnated with the pheromone mimic. of the sticky base of the traps, one lure Figure 2a: Fresh eggs can be found on new crop nuts after These lures are used to attract male moths hull split. per trap (Figure 3c) into traps. The presence of male moths in traps indicates that females are also likely to • Position traps as high as is practical be active, mating and laying eggs. A record of where they can be accessed easily for the moths trapped each week will show how regular inspection the population varies over time (Figure 3a). • Place traps so they will be shaded from When trapping for carob moth: direct sunlight during the hot summer months and be out of the way of • Use white ‘Delta’ traps which contain a machinery sticky base to capture insects (Figure 3b) - these are available through most • Hang the traps by twisting their wire Figure 2b: An infested nut mummy showing carob moth agricultural suppliers handle around a branch so the trap chewing damage, frass and a silken cocoon enclosing a cannot swing freely in the wind pupa. • Store new lures in a refrigerator or freezer, and handle them with clean Almond Board of Australia Inc. P + 61 8 8582 2055 l F + 61 8 8582 3503 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 80 70 60 50 40 30 Average carob moths per trap per moths carob Average 20 10 0 2-Jan 9-Jan 4-Jun 3-Oct 2-Apr 9-Apr 5-Sep 6-Feb 5-Dec 1-Aug 8-Aug 7-Nov 5-Mar 7-May 16-Jan 23-Jan 30-Jan 11-Jun 18-Jun 25-Jun 10-Oct 17-Oct 24-Oct 31-Oct 16-Apr 23-Apr 30-Apr 12-Sep 19-Sep 26-Sep 13-Feb 20-Feb 27-Feb 12-Dec 19-Dec 26-Dec 15-Aug 22-Aug 29-Aug 14-Nov 21-Nov 28-Nov 12-Mar 19-Mar 26-Mar 14-May 21-May 28-May Figure 3a: Record of moths trapped each week demonstrating how population varies over time • Locate traps in orchard areas that have indicates that three traps are sufficient to Where three traps are used, all three a history of carob moth damage, or that provide accurate data. A single trap will still should have new lures installed before the may be at higher risk, e.g. with other host provide useful data, but its accuracy will be start of the season (late winter). The lure plants like pistachio and citrus nearby influenced more by the changes in lure age. replacement routine in Table 2 will ensure that during the season, the three lures will • Position traps at least 100 metres apart always be a mix of new, middle-aged and old. so that each trap is at the centre of a 1 ha Table 2: Recommended lure replacement routine.