Ptinus Fur (L.) in Stored Grain - Biology, Seasonal Occurrence and Control Using a Surface Insecticidal Admixture
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Proceedmqs of the 7th Iniernatumal Workmg Conference an Stored-product Protectwn - Volume 1 The white-marked spider beetle, Ptinus fur (L.) in stored grain - biology, seasonal occurrence and control using a surface insecticidal admixture DM Armitage", M P Kellyl, K Amos' , S Schaannmg/ and W Spagnolr' Abstract conditions, relatively poor hygiene, and the presence of Ptuius fur (L ) has recently been identified as the most vertebrate pests inside the building Some of these species frequently occurnng, If not the most numerous, beetle pest are quite slow breeding, usually With only one generation of Bntrsh gram stores Previous work has mdicated that It IS per year One such IS the white-marked spider beetle, a nocturnal species and free-roaming adults occur between Pimus fur (L) which has hitherto been mostly October and June It pupates m August and eggs laid after disregarded and no Significant research has been conducted the turn of the year diapause as larvae until the following on ItS control III bulk gram year Females need free water to OVIPOSItand estimates of In a recent survey of commercial gram stores (Pnckett total eggs laid range from 38 - 100 while longevity estimates and Muggleton, 1991), ptmids were second only to mites vary between 84 and 224 days Records of pitfall trapping m and psocids m frequency of occurrence of mvertebrate pests two British stores showed that senous infestations developed (Table 1) Pimus fur was the commonest ptimd and was on gram stored for 4 years or more, With seasonal outbreaks found on 37% of 157 sites or 25% of 283 stores It was also in winter Adults of two populations from different stores present m 22% of 187 mills (Prickett, 1994) The mere were exposed to pmmiphos-methyl and etnmfos for 2 and 7 presence of an msect does not necessanly indicate a senous days and the latter pestrcide produced a higher mortality As infestauon but nevertheless IS enough for a market rejection a result of these pronusmg laboratory efficacy tests, a full of the gram However, senous infestations do occur and 4 scale surface treatment was earned out III a 16,000 tonne III bulk gram store The surface treatment was very uneven stores on 2 sites the Midlands have suffered ptmid and exceeded the recommended dose but It was clear that It problems smce November 1988 largely eradicated the mfestation, despite the natural decline m spider beetle population throughout the test There was Table 1. The number and proportion of commercial sites and no apparent difference between the effectiveness of the 2 stores thereupon m which Ptmus was detected pesncrdes m this commercial-scale test Sites Stores No % No % P fur only 45 28 7 57 20 1 P fur + P tectus 31 8 3 13 46 Introduction P fur + P pusdlu« 1 o 61o 4 Bulk cereal grams stored for extended penods m the UK are Total 59 37 0 71 25 1 always at nsk from mfestation by a range of msect and mite storage pests Many of these are well recognised, and their It IS clear that this IS one species whose pest status IS prevention and control has been the subject of research for many years In addition to these "pnmary pests', It has changing or has already changed and accordingly, a long been known that gram stores frequently carry a lower prehmmary research programme was mrtiated This level of infestation of 'secondary pests' , many of which are compnsed a summary of known aspects of the msect's associated With long storage penods, undisturbed biology, a collection of records of population changes in a commercial store, hrruted laboratory trials on the efficacy of etnmfos and pmmiphos-methyl on adults and an attempt to 1 Central Science Laboratory. Muustry of Agriculture, Fisheries and Food. Sand Hutton, York Y04 ILZ UK elmunate the pest on a commercial scale by a surface 2 Grovemere Merchants. Lancaster Way, Ely. Cambndgeshire CB6 admixture expenment which incorporated a companson of 3NP both chemicals 51 Proceedmqs of the 7th Internatwnal Workmg Conference on Stored-product Protection - Volume 1 as low as 8°C (Godan, 1952) A small proportion of adult A Brief Summary of the Biology males has been observed to fly (Woodroffe, 1953) and of Ptinus fur maximum activity occurs at 10-1St: The biology was systematically studied by Howe and The natural history of this species was studied by Braune Burges (1951) from whom Table 2 has been extracted (1948) and most of the details that follow relate to his They used vanous diets to raise the msects but as the study Eggs are laid m sheltered places where they adhere differences between most of them were not significant, the and develop mto active larvae which normally develop figures below are based on average values for the 3 diets No through 3 mstars They pupate m August m a cavity which diapause was noted at 30t: but eggs did not hatch Mortality they seal With webbmg, where they develop mto adults of larvae vaned from over 50% on wheatfeed at 30t: and at which remam for a penod m the coccoon while they mature 20°C, about 23% on fishmeal at 23t: to 7- 8% on sieved sexually The adults are only found between October and fishmeal and a synthetic diet at 23°C June and die off m the latter month Larvae from eggs laid Braune (1948) gave figures of 26 days for egg between October and December enter the pupal stage the development under ambient conditions, 18 - 19 days for followmg summer Those laid between March and June are pupal development and 30 - 35 days for the penod m the not fully grown by August and walt a further year before cocoon Pre-oviposition was up to 20 days but more normally pupal metamorphosis takes place There are only 2 mstars m 10 days when sufficient fluid was available Five eggs laid m this case, so the full penod of development IS well over a late October, early November took 10 - 11 months (300- year The turn of the year marks the boundary between 360 days) to become adults Two laid m late Apnl , early these two types and about 1/3 of the eggs laid then complete May took 17 and 19 months (510 - 570 days) while 2 laid m development m the same year and the remamder contmue January took 9 months (270 days) and 21 months (630 mto the second year This' diapause ' makes the production days) of large numbers for laboratory studies problematical and Howe and Burges (1951) found that only 38 eggs were this explams the dearth of information on an Important and laid by females, mamly over a 12 week penod but Braune Widespread pest Howe and Burges (1951) noted that all (1948) quoted 100 as the figure m the summary of his study their diapausmg msects were males and obtamed as many as 168 (52, 44, 168, 56) usmg a diet The adults are scavangers and, as well as foodstuffs Will of dead flies and milk This extended the life to about 9 eat dead insects, for mstance m the nests of wasps, rodent months or 148 days (88, 162, 149, 90, 173, 224 days) faeces, skms of birds and mammals and are a pest of compared to 32 - 59 days when starved or on a diet of rye museum specimens However, for maximum productivity, bran and flies Howe and Burges (1951) stated that males they benefit from a protemaceous diet and free water IS Irved , on average for 12 1 weeks (85 days), females for 14 essential for the female to produce eggs weeks (98 days) Zakladnoi and Ratnova (1987) also give They aVOId light and are mamly nocturnal, activity figures of longevity of adult P fur at moderate (Table 3) peakmg between 10 p m and 11 p m Most are found m and survival times at low (Table 4) temperature November Oviposition has been observed at temperatures Table 2. Time m days for the development of Ptvnus fur at 70% r h (abridged from Howe and Burges, 1951) Temp °C 30 23 20 no diapause diapause no diapause diapause egg penod x 16 5 19 5 larva 88 5 64 4 288 5 68 5 352 6 pupa 17 8 16 6 17 7 18 8 21 1 pre-emerg 39 41 2 44 2 53 6 38 4 egg-adult 96 8 329 2 106 7 368 3 egg-emerg 136 4 370 7 158 6 411 3 x = no development -=no data Table 3. Longevity of P fur (days) accordmg to L Gurvich [CIted m Zakladnoi and Ratnova (1987) ] °C 10-13 15 -18 18-22 23-15 25-30 males 42-59 32-61 46-61 24-49 11-18 females 38-92 62-71 61-113 34-87 10-30 52 Proceedings of the 7th International Working Conference on Stored-product Protection - Volume 1 Table 4. Low temperature longevity of P. fur stages (days) incubation, during initial visits to the 2 bulk grain stores. at 75% r. h. after R. Ushatinskaya [cited in The emergence of beetles from these samples was very Zakladnoi and Ratnova (1987) J. slow, producing only low numbers of adults and as a result, larger numbers of adult beetles were collected directly from 'C 0 -5 -10 -15 the store to be used in preliminary tests. Two admixture adult 79 72 29 9 pesticides, pirimiphos-methyl (Actellic) and etrimfos egg 186 97 31 9 ( Satisfar ), commercially available as 0.2 % active larva 219 164 36 17 ingredient dust formulations, were used in these standard laboratory toxicological tests.