This file was created by scanning the printed publication. Errors identified by the software have been corrected; however, some errors may remain. Cone and Seed Insects Associated with Pifton Pine Jose F. Negron 1 Abstract.-This paper summarizes current biological information on insects that feed in cones and seeds of pinon pine, Pinus edulis Engelm. Evidence indicates that there is a need for additional studies relating the biology and potential impacts of cone and seed insects in pinon pine. INTRODUCTION INSECTS REPORTED ON CONE AND SEED OF PINON PINE Pifion nut harvest holds a potentially signifi­ cant commercial value (Schwab 1993; Norwick et al. 1993) in this forest type. Indeed, as a result of a 1. Ernobius montanus Fall (Coleoptera: request by the Southern Pueblos Governor's An obiidae). Council, the Bureau of Indian Affairs (BIA) has ini­ tiated a Pilot Woodlands Management Program. As Most beetles in this beetle's family feed on dry part of this program the BIA is cooperating with vegetable materials, under bark on dead trees, in the USDA Forest Service, Rocky Mountain Forest seeds or stems of plants, or as larvae on fungi and Range Experiment Station in a series of nut (Borror et al. 1981). Species that inhabit cones are production studies (Schwab 1993). all in the genus Ernobius. Ernobius nwntanus Fall has Information on insect associates of cone and been reported from various hosts in southern Cali­ seed of pifton pine, Pinus edulis Engelm. is limited, fornia including Coulter pine, Pinus coulteri D. Don; and even less is known about their impacts on cone Jeffrey pine, Pinus jeffreyi Grev & Balf.; pinon pine; crops. Little (1943) indicated that cone and seed in­ singleleaf pifton, Pinus nwnophylla Torr.& Frem.; and sects destroy large portions of marketable crops ponderosa pine, Pinus ponderosa Laws. (Hedlin et yearly; first year strobili are attacked mostly by gall al. 1980). Adult beetles are 3-5 mm long, slender, midges (Cecidomyiidae) and second year strobili and reddish to dull-brown. Larvae are white, by cone moths and cone beetles (Little 1943,1944). scarabaeiform, and have well developed legs (Keen The limited available information is scattered in 1958). Keen (1958) also states that larvae feed in the literature. Little (1943) and Keen (1958) sum­ old, dry cones and dead twigs. During the winter marized the available information to date. Since larvae can be found on that year's cone crop. then there have been no further attempts to com­ Emergence is from July to August. pile available information into a comprehensive Another species in this group, Ernobius punctu­ treatment. This paper will: 1) summarize known latus (LeConte), feeds in mature or dead cones of biological information on insects reported on cones Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco; and seeds of pifton pine and 2) discuss considera­ knobcone, Pinus attenuata Lemmon; Monterrey tions for future strategies for additional entomo­ pine, Pinus radiata D. Don; and ponderosa pine logical research on cone and seed insects of pinon (Hedlin et al. 1980). Hedlin and Stickland (1959) pine and their impacts. A summary of available in­ stated that this insect feeds only in rn.qture and formation on impacts and monitoring of insects af­ dead cones and that it is not important in seed fecting cones and seeds of other coniferous seed production but may affect cones in storage prior to production systems is pesented in Appendix 1. seed extraction. Hedlin et al. (1980) state that re­ Such information can serve as foundation for simi­ ports of this insect killing cones are probably in er­ lar studies in pifton pine. ror and that the species is a scavenger in dead 1Research Entomologist, Rocky Mountain Forest and Range Ex­ periment Station, Fort Collins, CO. 97 cones. Ernobius granulatus LeConte was originally Forcella (1980) suggested that cone predation reported by Allen and Coyne (1956) as a herbivore by C. edulis is influenced by the frequency and of living cones of longleaf pine, Pinus palustris Mill. magnitude of cone crops. He stated that variability However, Ebel (1964) demonstrated that it was also in cone crop size is caused by cool temperatures a secondary invader of dead cones. Two other spe­ during a 1-2 week interval in late summer 2 years cies in the genus, however, are known to attack prior to cone maturation, when the cones are still healthy, green cones of various conifers. Ernobius in primordial stage. Since the occurrence of these conicola Fisher infests dry cones but also attacks cool temperatures are erratic in nature, the result is green cones of Monterey cypress, Cupressus macro­ erra tic cone production. carpa Gordon, in coastal California (Frankie 1973). These variable cone crops do not support high Ruckes (1958) demonstrated that Ernobius average beetle populations that can devastate mast melanoventris Ruckes attacks green cones of Jeffrey crops, thus allowing viable seed to be available for pine in California. Ernobius bicolor White has been regeneration. Forcella (1980) also states that pmon reported infesting year-old, older cones, and stored populations at the edges of its geographic ranges cones of black spruce, Picea mariana (Mill.) B.S.P' are more stable in annual cone production. This (Schooley 1983). host stability supports stable beetle populations Since little biological information is known that are able to limit the amount of viable seed about E. montanus and considering that the genus available for regeneration and thereby limit the displays variability in its habits, it is important to range of the tree species. clarify this insect's role in pinon pine. 2. Conophthorus edulis Hopkins 3. Conotrachelus neomexicanus Fall (Coleoptera: Scolytidae), pinon cone (Coleoptera: Curculionidae). beet/e. Little (1943, 1944) reported that the larval stage Beetles in the genus Conophthorus are com­ of an unidentified species of Conotrachelus com­ monly referred to as cone beetles. They are bark monly destroys pinon cones during June and July. beetles that attack cones of pines and are among The larval stage of Conotrachelus neomexicanus Fall, the most destructive insects of cones and seeds in the pine cone weevil, which feeds on the scales and North America. Twelve species are known from seeds -of ponderosa pine cones, has been collected North America and eleven of them attack cones from pinon pine in Mesa Verde, Colorado (Hedlin et al. 1980). Conophthorus edulis Hopkins is (Bodenham et al. 1976), and is probably the species the smallest in the group, ·about 1.25-2.75 mm long. referred to by Little (1943, 1944). Adults of C. neo­ It is dark colored with a dark red elytra. The only mexicanus, which are ca 6 mm long and gray-brown, host for this species is pmon pine and the insect oc­ overwinter in the ground, emerge in the spring, curs throughout the range of the host in Arizona, . and feed on new shoots and male flowers. After New Mexico, Colorado (Keen 1958), and Oklahoma mating, the female makes a hole on the tip of a (Forcella 1980). Adult beetles attack second~year cone scale, oviposits, and uses frass to cover the strobili in Mayor June by boring at the base of the hole. Larvae are 9-10 mm when fully developed cone, constructing a gallery through the cone axis, and white to pink with a brown head capsule. and laying eggs along the way. Larvae, which are They develop in the cone and destroy it. When lar­ C-shaped, legless, and whitish with amber to vae complete development they chew an exit hole, brown heads, feed and develop inside the cone, drop to the ground, and pupate. Transformation pupate in August, and later transform into adults into the adult is completed after a few days. The that overwinter inside the cone. The cone is killed adult hardens in the pupal cell, emerges, begins to in the process and falls to the ground or persists on feed on shoots and later returns to the litter to the tree. Emergence occurs the following spring in overwinter (Bodenham et al. 1976). In certain areas April and May, leaving through small holes on this weevil may kill much of the ponderosa pine dead cones, and the cycle begins again (Little 1943, cone crop, but there are few records of occurrence 1944; Keen 1958; Furniss and Carolin 1977). A small (Hedlin et al. 1980). Conotrachelus neomexicanus has pteromalid wasp, Acerocephala atroviolacea Crawf., has been collected from Arizona, New Mexico, Colo­ been reared from cones infested with·C. edulis, and is rado, Nebraska, South Dakota, and Montana thought to be parasitic on the beetle (Keen 1958). (Bodenham et al. 1976). 98 4. Hapleginella conicola (Greene) (Diptera: Gall (1992) reported records from Connecticut, New Chloropidae). York, Pennsylvania, and Ontario and suggested that the species is still expanding its range. Adults of this species are small shiny black The following biological information is taken flies about 1 mm long. Larvae are colorless to from Koerber (1963), Krugman and Koerber (1969), whitish maggots, elongated, and ca 2 mm long. and Hedlin et al. (1980). Adults are 15-18 mm long Larvae are active from the fall through spring, and 4-6 mm wide, reddish brown to dark gray with feeding in scales and seeds and destroying whitish pubescence, with a narrow zig-zagged line cones. Pupation occurs in April and adults across the fore wings, and laterally expanded tibiae emerge from late April to mid-July. A second on the hind legs. Eggs are 2 mm long and 1.2 mm generation may occur in late summer (Keen wide, light brown when first laid and turn reddish 1958). Hosts include white fir, Abies concolor brown as the nymphs develop. Leptoglossus occiden­ (Gord & Glend.) Lindl.; Shasta red fir, Abies talis is univoltine and overwinters as an adult in magnifica Lemm.; Jeffrey pine; ponderosa pine; protected locations.