Carpophilus are highly active pests that have several generations per year with females laying an average of 1,071 eggs, with eggs hatching in 1-4 days, and larval development taking 4-14 days. They are also strong fliers with distances greater than 4km achieved. Carpophilus are very resilient pests and can hibernate as mature larvae, pupae and adults. Like most pests, carpophilus is affected by environmental conditions with relative humidity less than 40% reducing larvae and egg laying; consequently, dry conditions in the previous autumn and winter reduce spring populations. One could infer the wet seasons of 2010/11 and 2011/12 could still be causing us issues. A quick review of the weather conditions also indicates the relative humidity for the 2013/14 season was higher than the 2012/13 season, particularly when comparing the spring period. This may explain why we have seen more pest pressure this season in both almonds and stone fruit. The host range of carpophilus is also extensive and broadening, where in recent years they have become significant pests of new crops with substantial crop losses in cherries and strawberries. Whilst it is not known why carpophilus has become attracted to almonds, it’s thought the volatiles from ripening or rotting (mummies) fruit are likely to play a role, just as it does in stone fruit. It should be remembered almonds are from the same genus (i.e. Prunus ) as peaches, apricots, cherries, etc. Other than cause physical damage and rapid breakdown to stone fruit, carpophilus also can cause indirect damage by serving as a vector of brown rot inoculum ( Monilinia spp .), which frequently develops at the sites of beetle entry. In almonds, there have been no reports of almonds affected by Monilinia spp . or alternatively Aspergillus spp . (aflatoxin producing) fungal spores, but the physical damage has been quite severe. These relationships will need to be watched carefully. What is concerning with the behaviour of carpophilus is they penetrate and burrow into the kernel and reside there for some time (Figure 3), and don’t just feed on the surface as carob moth tend to. This penetrating behaviour and visual presence later in the supply chain makes the product redundant and even with further processing can’t be salvaged. The only market left is oil and for those growers that aren’t aware this price is the lowest of the lows attracting less than $0.80/kg. Management Options Like the management of most pests, success is achieved with an integrated approach. Orchard hygiene Unfortunately or fortunately, depending on how you look at it, successful management of carpophilus is likely to be associated with good orchard hygiene, aka reduction in mummy numbers. Unfortunately, mummy reduction is easier said than done as it is a major flaw of our most prominent variety Nonpareil. Fortunately, mummies are the source of many other problems (e.g. hull rot inoculum, Aspergillus inoculum, and carob moth), so every effort invested in reducing mummy numbers should pay dividends. It’s worth highlighting mummy reduction is just not a matter of reducing over wintering fruit by employing effective harvesting or re-shaking practices, but to also employ a preventative approach of avoiding hull rot and “rotting fruit”. It cannot be stressed enough that mummy reduction and orchard hygiene is a non-negotiable in the successful management of an almond orchard. Monitor It will be important to identify high risk blocks from a past history of damage. This history is achieved two ways:
Figure 3: Carpophilus beetle burrowing into kernels
Active monitoring in-season. Establish a trapping grid, check traps weekly, identify species, record and plot results, and analyse trends. Monitoring can be undertaken very quickly and cheaply using green funnel traps hung at eye level inside the orchard, and an attractant supplied by Insect Management Services or manufactured using the following recipe: 1. Dissolve 1g of dry yeast in 200ml of 100% apple juice. • Absorb mixture into 10g of polyacrylamide granules (e.g. Yates Water Crystals). • Wait an hour to allow juice to be absorbed fully. • Place resultant gel in a 300ml plastic container and cover with a fine mosquito mesh secured with a rubber band to keep beetles out of the gel container. • Place the gel container in the bottom of funnel trap. • Place a 1cm 2 piece of a household insecticide strip (i.e. dichlorvos) inside but near the top of the trap. The attractant is to be replaced approximately every two weeks, and to measure the beetle population use a 50ml measuring cylinder (beetle no. = 200 x (vol (ml) – 0.18). Please contact state government chemical use laws regarding the use of this system.