The Beetle Mordellistena Parvula Gyll
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THE BEETLE MORDELLISTENA PARVULA GYLL. (COLEOPTERA, MORDELLIDAE), A NEW SUNFLOWER PEST IN ROMANIA Marin C. Voicu1, Valeria Ivancia1 ABSTRACT MATERIALS AND METHODS Aspects of biology and ecology of the beetle Mordellistena parvula Gyll., a new sunflower (Helianthus annuus L.) pest are presented for the first time in Romania. Mordellistena The research was carried out in sunflower parvula Gyll. is a univoltine species, hibernating as third crops situated in Agricultural Research Station instar larva, inside of sunflower stems and roots. Larvae of Mordellistena parvula Gyll. feed with the stem pith of sun- - Podu Iloaiei area, county Iaºi, between 1977- flower. Natural enemies of this pest have not been reported 1995. till now. Some resistance and tolerance to the attack of this Observations were made particularly on pest was recorded in inbred lines and hybrids of sunflower tested. the pest larvae developing in sunflower stems. Phenological stages of egg laying by the Key words: Mordellistena parvula Gyll., sunflower adults, the place of penetration of the first in- star larvae into the petiole sheath and the de- INTRODUCTION velopment of the larvae were observed. Ad- vancing directions of the larvae through the he family of Mordellidae comprises about stem pith during their feeding period, the po- T600 species of small insects, with dark sition and shape of the galleries as well as the colored tegument, sometimes with light number of larvae/stem were also recorded. colored drawings. The surface of the body is The period of hibernation, including the mo- covered by silky hair, disposed in stripes or ment of adult occurrence was determined. spots, rarely with bright reflections. All these observations were made peri- The length of the adult insects varies be- odically by sectioning the sunflower stems. tween 2 and 4 mm. The adult insects are very active and good flyers, being observed on the flowers of Umbelliferae and Compositae spe- RESULTS AND DISCUSSIONS cies. Some species of Mordellidae could hop At the beginning and in the middle of using the posterior legs and the tip of the ab- May, sunflower crops are visited by a large domen. number of species of insects belonging to the The family Mordellidae is spread in orders Homoptera, Heteroptera, Diptera, Col- Europe, Middle Orient and Asia, up to Mon- eoptera, among which Mordellistena parvula golia (Balachowschy, 1962). Gyll. (Figure 1). Until now, the beetle Mordellistena par- The body of this pest is narrow, laterally vula Gyll. (syn: Mordella parvula Gyll., Mor- flatted and sharpened at the posterior side. The della troglodytes Mann., Mordella pusilla head is short, vertically inserted on the proto- Redt.) has not been reported as harmful for thorax, bearing large oval prominent eyes. The sunflower in Romania (Vrânceanu, 1974). The antennae have 11 articles and are fixed behind larvae of this beetle have been found inside of the eyes. The elitra are slightly convex, nar- the stem of some sunflower inbreds and hy- rowed at the posterior side, letting the py- brids at Agricultural Research Station - Podu gidium partially uncovered. The legs are long Iloaiei, and the adults in the samples collected and covered with hairs which are longer at the by entomologic netting. posterior pair. The tarsi have 5 articles at the This study presents some aspects of the first pair of legs and only four at the posterior biology and ecology of the species Mordellis- pair. The color of the body is dark gray. The tena parvula Gyll. as sunflower pest. length of the body of adult insects varies be- 1 Agricultural Research Station (ARS) Podu-Iloaiei, County Iaºi 83 84 Number 5 - 6 / 1996 ROMANIAN AGRICULTURAL RESEARCH A B Figure 1. Second (A) and third (B) instar larvae of Mordellistena parvula Gyll A B Figure 2. Longitudinal sections through the petiole sheath perforated (A) and non-perforated (B) by Mordellistena parvula Gyll. larvae tween 2.6 and 3.1 mm. First instar larvae of Mordellistena par- Mordellistena parvula Gyll. is an exclu- vula Gyll. have a length of 3 mm. The larvae sively phytophagous species in the larval of the second instar are 6-8 mm long (Figure 1 stage, in the stage of adult feeding with the A), have a milky-white color, are apodal, with pollen from different spontaneous plants, par- cephalic capsule colored in light brown. As ticularly from Umbelliferae. The adults de- they feed, the larvae turn to yellow. The third velop successfully, from the pupae from soil instar larvae are 10 mm long and they reach and from stem and root rests, at the beginning the maturity toward the end of October. The of May till the beginning of June. The females cephalic capsule of the third instar larvae is are more numerous and the males are rare. Af- light brown (Figure 1 B). ter a period of feeding they pair, and after a Narrow galleries could be observed in the short while lay the eggs gradually. pith of the attacked plants, being oriented The eggs are laid into the superior epi- more or less towards the base of the stems dermis at the base of sunflower leaf sheaths, (Figure 2). The larvae damage also sometimes beginning with the 6th pair of leaves. the conductive vessels in the stem penetration A female can lay 1-3 eggs on a single area (Figure 3). plant. From our observations, several females Solid excreta, resulted from the larval can lay eggs on a sunflower stem so that feeding with plant tissues, are stored within sometimes up to 14 larvae could be present on the galleries from place to place, as the larvae the same plant. advance. A number of 2 till 8 larvae were gen- During the plant development, the fe- erally found. males lay eggs at the base of leaf sheaths from Hard attacks cause the reduction of seed superior levels and first instar larvae occur. yield/plant and root and stem lodging (Figure The pest has three larval stages. 4) (particularly when strong winds occur) and M.C. VOICU AND V. IVANCIA: THE BEETLE MORDELLISTENA PARVULA GYLL. (COLEOPTERA, MORDELLIDAE), 85 A NEW SUNFLOWER PEST IN ROMANIA Figure 3. Cross-sections through sunflower stem pith: Figure 4. Sunflower stem breaking caused by the attak galleries (g) created by Mordellistena parvula Gyll. of Mordellistena parvula Gyll. larvae and central gallery (gc) subsequently important losses at mechanical None of the natural enemies of this pest harvest. Sawdust or orifices were not observed has been mentioned in the literature (Thomp- with unaided eye at the point where the eggs son and Simonds, 1964; 1965). were laid and the larvae penetrated into the Host plants. In Romania, the pest devel- stem, as compared with the European corn ops on the cultivated or spontaneous sun- borer (Ostrinia nubilalis Hbn). flower (Helianthus annuus L.) Due to the larval attack, a central gallery could more or less occur in the stem pith, CONCLUSIONS which usually is larger towards the stem base. In October, larvae of the second and third in- The species Mordellistena parvula Gyll. star could be observed concomitantly in sun- was observed in Romania as sunflower pest flower stems and roots. for the first time. The pest hibernates as last instar larva, in Data concerning the biology and ecology stems immediately near the root neck, as well (the moment of adult occurrence, egg laying as in roots. In spring, in month of May, the onto the host plant, the larval instars, the larvae which hibernate in roots, move upwards mode of attack, the hibernation) of this new through the pith (till to the area where the stem pest were recorded. was sectioned) and pupate. The obsevations made several years and Beetle develop from pupae. during the whole vegetation period of host The mode of attack. The larvae attack plant led to the conclusion that Mordellistena the sheath of the leaf petioles, then the con- parvula Gyll. is a univoltine species under ductive vessels and the stem pith of sunflower climatic conditions of Romania. plants. The larvae feed permanently with the Some sunflower inbred and hybrids were pith, inside the stems with their mouth frame- found to be resistant or tolerant to the attack of work of "breaking and chewing" type. Toward Mordellistena parvula Gyll. the end of the larval feeding period, close to the beginning of hibernation stage, fully REFERENCES crowded together excreta are encountered in Balachowschy, S.A., 1962. Entomologie appliquée à l’agriculture, tome 1, Coléoptères, Masson et Cié, Paris. gallery on segments of 1-2.8 mm length. In Thompson, W.R. and Simonds, J.F., 1964. A Catalogue of the continuation of these excreta deposits a gallery Parasites and Predators of Insect Pests. Section 3. Preda- ortion of 1.7 - 3.2 cm length is partially lined tor Host Catalogue, Commonwealth Institute of Biological Control, Ottawa, 1-204. with a very fine cloth like a veil of white- Thompson, W.R. and Simonds, J.F., 1965. A Catalogue of the grayish colour, where the hibernating larva is Parasites and Predators of Insect Pests. Section 4. Host Predator Catalogue, Commonwealth Institute of Biological found. Control, Ottawa, 1-198. All galleries from the stems are directed Vrânceanu, A.V., 1974. Floarea soarelui, Edit. Acad. R.S.România, towards the base of the plants. 286-297. .