Page 43 - SA Fruit Journal VOLUME 14

Fuller’s rose weevil found in stone fruit orchards in the Robertson areaF G h VAN ZyL Business Unit Manager, Pathology & Registration, SAPO Trust Private Bag X5023, Stellenbosch 7599. Tel: 021 887 6823 Email: ferdi@saplant.co.zaThe weevil that was identified in stone fruit trees in Robertson, klein-karoo during September 2014 was not the Diaprepes root weevil, but was identified as Fuller’s rose weevil (Naupactus godmanni).The Fuller rose beetle (FRB), Naupactus godmanni (Crotch), sometimes known as the Fuller's rose weevil, caused consider- able damage to winter roses when it was first reported in the United States, California in 1879 (Chadwick 1965). Damage was also re- ported on other ornamental plants including camellias, geraniums, primroses, carnations, dracaenas, azaleas, cissus, begonias, lilies, and horticultural crops such as citrus, per- simmon, apple, peach, plum, apricot, straw- berry, raspberry, and blackberry (Chadwick 1965).DistributionFRB is generally a cosmopolitan species found widely distributed in North and South America, Europe, the Mediterranean coun- tries, South Africa, Australia and many Pa- cific islands (see world distribution map). (CABI 2005).Larvae of Fuller’s rose weevil.curved towards the ground. As the elytra (wing covers) are fused, the insect cannot fly.Egg: The yellowish cylindrical eggs, 1 mm (1/25 inch) long, are laid in a mass and cov- ered with a white sticky material. They are placed in cracks and crevices of bark, be- tween leaves, and under fruit calyces.Larva: The white larva, which is legless, has a yellowish head capsule with contrasting black mandibles. When fully grown, it measures 10 to 12 mm (nearly1/2 inch) in length.World distribution of the Fuller rose beetle (FRB), Naupactus godmanni (Crotch), as of 2005. Illustration by CAB International.BiologyThe FRB generally overwinters as larvae in the soil. Only females are known for this spe- cies, and reproduction occurs without ferti- lization, a phenomenon known as partheno- genesis (Chadwick 1965).The female lays eggs in a mass and cov- TEGNOLOGIE 40 FEB | MAART 2015Fuller’s rose weevil.ers them with a white sticky material. In gen- eral, eggs are typically stuck under stones, in bark crevices, inside calyx lobes of fruits, or in curled dead leaves (CABI 2005). Up to 1 000 eggs have been reported as laid by an adult female during its lifetime (Masaki et al. 1996). It takes from two to six weeks for eggs to hatch, depending upon temperature (Lakin and Morse 1989).After hatching, the legless larva drops to the ground, enters the soil, and feeds on the roots for the next eight to ten months if there is only a single generation. The larva is active to a depth of 61 cm, but the third instar larva moves closer to the soil surface to prepare a smooth walled earthen cell prior to pupa- tion. The larva rotates its abdomen and pro- duces anal secretions that line the walls of the cell. The pupal stage lasts for one and half to two months. Adults emerge and crawl up to their host plant to feed on the leaves, buds or flowers (roses). Adults live for three to eight months (Masaki et al. 1996).Hosts PlantsThe number of host plants for FRB is very ex- tensive, but the primary hosts include CitrusDescriptionThe description of the life stages is mainly based on Woodruff and Bullock (1979). Adult: The brownish grey (with intermixed white scales) adults are 6 to 8.5 mm long (~ 1/3 inch). Eyes are in lateral position and appear bulging; rostrum (snout) is slightly