JARQ 24, 149-155 (1990)

Ecology of grandella and Its Seasonal Changes in Population Density in Peruvian Amazon Forest

Saburo YAMAZAKI, Akihiko TAKETANI, Kazuyuki FUJITA, Carlos VASQUES P.• and ToshiyalKEDA

Abstract Hypsipyla grandella is the most harmful pest against Meliaceae, including spp. andSwietenia macrophylla, in the tropics of the South American region. Field surveys on damages and bionomics ofH. grandella conducted in the Peruvian Amazon area under the Forest Regeneration Experiment Project during the period 1983 to 1987 revealed that the population density of H. grandella increased rapidly in the rainy season, i.e. September or October to May. There were some cases where the damage ratios exceeding 50% had resulted in failures in establishing plantations because of the repeated attacks by high density population ofH. grandella. The availability of feed stuffs for this species inc re as ed in the rainy season, while decreased in the dry season. The seasonal change of H. grandella density was closely correlated with that of newly sprouted host trees. C. odorata was more susceptible to H. grandella attack than S. macrophylla was. Natural enemies identified were several parasitic wasps, a few predatory wasps, a nematode, ants and fungi. Both wasps may greatly contribute to control H. grandella in nature. J:,,.1ixed planting with other tree species than Meliaceae was not successful in reducing insect damages in line plantations. Since Hypsipyla adults seem to prefer young plants of the host species, planting in clear cut areas may help them identify their host trees for mating and laying eggs. Therefore, in is not advisable to employ clear cutting of more than 5 m-width or clean weeding in plantation. Planting in a small patch may be worth of testing. Natural regeneration under spot planting with shading by a forest canopy would give some effect on reducing the in sect attack, though the tree growth may be reduced.

Discipline: Insect pest Additional key words: Cedrela o dorata ( Cedro), mahogany shootborer, Swi etenia macroph yll a (Caoba)

of these lumbers are very high, reflecting their wide Introduction uses for furniture, architecture and durable goods. On the other hand, the prices of other kind of trees A number of useful tree species in the Peruvian have also been gradually rising in recent years. Amazon area have seriously deteriorated in terms of Taking into account this situation, the Peruvian amount and genetic resources as well in the last Government has been making efforts in promoting several decades. At present, the population of the regeneration of degraded secondary forests or following three most valuable trees, i.e. Caoba depressed forests6>. ( macrophylla, mahogany in English), The Forest Regeneration Experiment Project in Cedro () and Ishipingo (Anburana Peruvian Amazon started in 1982 under the aid pro­ cearensis), is very small in size because of extensive gram of the Japan International Cooperation Agency and selective cuttings, burning and great difficulties (JICA). The objective of the project was to develop in natural regeneration. Therefore, the curre111 prices forest regeneration technology which should include

Forest Biology Division, Forestry and Forest Products Research Institute (Tsukuba, lbaraki, 305 Japan) • National Institute of Agriculture (Pucallpa, Peru) 150 JARQ 24(2) 1990 an effective utilization of the existing natural forest Table l. Fores! area in Peru resources in Peru by demonstrating afforestation of (IOOO ha) experimental forests9>. A T . Forest land Natural 1 Zone rn 1c1a to be Total Twenty seven species of useful trees were selected forest forest and planted for the regeneration experiment. The regenerated tree species planted had generally been in good shape Coastal zone 9SO 8 493 1,451 of growth both in height and volume in the first stage Mountain zone so 98 7,402 7,550 75,506 of the project. However, the most serious incidence Forest zone 73,000 8 2.498 took place thereafter. It was the destructive Total 74,000 114 10,393 84,507 outbreaks of three Meliaceae species, i.e., S. macrophyl/a, C. odorata and Cedrela jissilis (Cediro blanco), caused by the attack of mahogany shoot ation but to a lack of technology for regenerating borer, Hypsipyla grandella Zeller. the degraded secondary forest after migration farm­ 9 7 Matsui, M. > and Kobayashi, K. et at. > outlined ing or selective cuuings. The forests in the watershed the damage of Meliaceac spp. and the biology of of the Arna.z.on cover an area of about 40 million H. grandel/a, and emphasized the urgent necessity ha, which is the richest forest in Peru with a variety of further studies on biology and control method of of trees. Eighty percent of lumber production con­ H. grandella. sists of only a few species, i.e. Cedrela sp. (400/o), During the period 1986 to 1987, intensive studies Swietenia sp. (130/o) and Podocarpus sp. (110/o). were undertaken with major emphasis placed on However, utilization of other species has been biology, population dynamics and control method expanding in recent years owing to the development of H. grandella under cooperation of the Peruvian of wood processing technologies6>. and Japanese scien1ists12>. The present report ac­ Six species in the genus Hypsipyla have been iden­ counts for the resuhs of the studies on population tified in the world. Among them, two species, H. dynamics and ecology of H. grandella in relation to robusta Moore and H. gra11della Zeller, predominate its host trees. in large areas, giving serious damages to Meliaceae species. The distribution of these two species is 8 Forestry in Peru shown in Fig. t 1· >.

Forest areas in Peru are divided into three geo­ Stud y sites and design of planting graphic groups; i.e., coastal zone, mountain zone and Amazon forest zone. The forests in the Amazon While the Pacific coast area of Peru has an ex­ forest zone predominate, consisting of tropical rain tremely small precipitation, the inland area beyond forests. the Andes has much more precipitation, being The forests in each zone are further classified into covered by tropical rain forests. The study site is natural forest, artificial forest and forest to be located in Von Humboldt National Forest, approxi­ regenerated (Table I). Approximately 88% of the mately 80 km west of Pucallupa in the Peruvian total forest land is covered by a natural forest, but Amazon area. its ratio to others is decreasing very rapidly. The Annµal rainfall in the project area is approximately forest 10 be regenerated is mainly located in the 4,000 mm. A great portion of the rainfall concen­ mountain zone (7 10/o) and partly in the Amazon trates during the period October to April; monthly forest zone (240'/o) and the coastal zone (5%). rainfall sometimes exceeds 800 mm. Approximate­ Further regeneration or plantation is expected in the ly 700 ha of the forest land in the National Forest mountain zone, where a majority of the artificial was included for planned management under the forest (920'/o) has already been established with suc­ project, comprising 580 ha for plantation, 80 ha for cessful plantations of eucalyptus. In the Amazon natural regeneration, and 40 ha for demonstrated forest zone, on the other hand, the forest 10 be plantation. A half each of the experimental forest regenerated is still limited at present. This is 1101 land was plain and hilly. The study sites for plan­ attributed to a shortage of suitable land for regener- tation and demonstration were both selected in the 151

Fig. I. Gcographycal

plain area and those for natural regeneration were Ecology ol" Hypsipyla grandella Zeller in the hilly area. Entomological studies were undertaken mainly in Eggs are white for one day after oviposition, turn the plantations, where either C. odorata or S. mac­ yellow in two days, reddish yellow in three days, and rophylla dominated. Line plan1ations with I 00-200 then hatch. The duration of each larval stage which m leng1h were subjected to three types of clear cm­ compasses five or occasionally six instars is approx­ tings, i. e. 5, 10 and 30 min wid th. T hese types were imately 5 days and that of prepupa through pupa set up to evaluate an effect of shading on tree growth is about 10 days, and the adult survives for 5-7 as well as on alleviation of the damage caused by clays. One generation of H. grandella is approxi­ H. grandella. In the clear culling area with 5 m­ mately one and half month long, inducing six to width, young trees of either Cedre/a or Swietenia seven generations a year. were planted in every 5 m on the middle of line. Their inhabitation ranges from the top shoot to In the 10 m- width plantatio n, ei1her species above the base of young crees, but rarely 1.0 the roots. The was planted in every 10 m, being surrounded by four upper part of seedlings is inhabited mainly by young other trees but Meliaceae with an aim of protecting larvae and the lower part by elder larvae or pupae. it from the attack of Hypsipyla. In 30 m-width This indicates that larvae migrate downward on a plantation, five seedlings of ei ther Cedrela or Swiete­ young tree as they grow up. The eggs are separate­ nia were planted in every 5 m on a line, and seed­ ly laid on both surfaces of new leaves in general. lings of other tree species were planted alternatively However, if the seedlings have few or no fol iages, in two or three consecutive lines. This design was the eggs are laid on a stem, where newly produced employed with the same purpose of protecting Melia­ frasses are excreted nearby. 2 3 ceae from H. grandella anack • >. As well known, adult females prefer young trees In addition to field surveys on damages, biologi­ for their inhabitation due to the attractants released cal stud ies on H. grandella were conducted in the from new leaves. The females release a pheromone laboratory. in mating with males5>. 152 JARQ 24(2) 1990

Host plants Table 2. Damage ratios in various regeneration areas (1985-87) Hypsipyla spp. is closely associated with trees or Damaged ratios Planiing No. of 1recs shrubs of MeliaceM family. The host trees o!f of host plants method under surveys Hypsipyla spp. recorded so far include: Cedrela (%) mexicana ( = blanco), C. odorata, Chloroxylon L.P.11 swietenia, Chukrasia tabularis, Entandophragma 5 111 IV, 10,377 16 angolense, E. utile, Khaya anthotheca, K. gran­ 10 111 w. 3,304 26 dijoliola, K. ivorensis, K. nyasica, K. se11egale11sis, 30 OI IV. 5,673 19 Lovoa trichilioides, Swietenia macrophylla, S. P.c.21 1,668 10 31 mahogany, Toona australis, T. ciliata and T. Spo1 194 13 N.R.41 22 5 serra1a•.5l . 5 Ccdro > 62,83 24 Caoba51 6,t82 It Na tural enemies I): Li nc planting on clearly cut area IVilh the width of 5, 10 and 30 m. 2): Planting under canopy, 3): Spol pla111- Natural enemies so far identified are: a parasitic i11g, 4): Natural regeneration, 5): Damage ratios were nematode (Fam. Mermithidae), two parasitic was1>s inves1iga1cd on 1he stands where only a single species of either (Bracon sp., Trichogramma sp.), and a fungus (Beau­ Cedro or Caoba wns ptaniccl. veria sp.). Among them, a nematode, presumably Hexamermis albica11s (Nicle and Grijpma, 1974), rations among different widths of clear cutlings in­ shows the highest parasitoid against Hypsipylc1 dicated that the 10 111- width plantation received the larvae; the larval parasitism sometimes exceeds IO OJo . most serious damages, followed by the plots with Trichogramma sp., an egg parasite, gives I Oct/o o r the width of 30 m and 5 m. The smallest damage less in its parasitism. The eggs parasitized by in the 5 m-width plantalion mig_ht have probably Trichogramma sp. change their color from red to resulted from a greater crown coverage of neighbor­ black. Role of Bracon sp. and Beauveria sp. as a ing trees over the young Meliaceac than the case in mortality agent is rather limited. Several hunting 10 m-width. In 30 m-width plntations, there was wasps which belong to Family Vespidae and also a great coverage of surrounding trees which grew Hymcnoptera are observed quite often to drum on faster than Meliaceae did. However, such a differ­ the tree shoot, searching l'or the larvae of Hypsipy­ ence in coverage by canopy was not large enough la. Therefore, the role of 1he wasps as a control to clearly j ustify the damage variation and evaluate agent may probably be very impo rtan1. the planting methods as well. The surveys were also conducted in other three Damages of Meli aceae spp. in plantations and areas in addition lo the line plamation areas (Table other regenerat ion areas 2). The damage ratios in these areas were a ll less than those in the line plantations; in particular, the Intensive surveys on infestation levels were con­ ratio in the natural regeneration area was very small ducted during the period 1985 to 1987 to compare or 51r/o only. T he coverage of surrounding trees o n implications of tree species, size of trees and plant­ the canopy over the young Meliaceae spp. was gener­ ing methods (Table 2). The two Meliaceae spp., each ally greater in these areas than in the line plantatio n of which was planted in line plantations, were sub­ area. In this respect, a few explantations could be jected to comparison in regard to the damages caused made to justify the difference of damage ratios. by Hypsipyla spp. The damage ratio in Cedro plan­ First, the small ratio might be caused by the lack tations was 24%, whereas that in Caoba was 11 % . of new foliages of Meliaceae for female adult These early damages, which took place within 1- 2 to lay eggs on due to the less light intensity. Second, months after the Hypsipyla moved in, were much it might be associated with the barrier effect of sttr· less than those of the accumulated damages for the roundi ng trees for females to search for their hos1 following 2-3 years. plants. The line plantation areas, on the other hand, A comparison of the damage ratios in line plan- might provide a more suitable space for adult females 153 to search for their host plants and for males to meet 100 1.0 females to copulate. In the natural forest, where a light thinning accompanied by planting of some seedlings under the canopy was made in I 983, no infestation of Hypsipyla was observed on both Cedro and Caoba in the first year. ln the second year, only two plants of Cedro out of 19 in that plot were infested, while the infestation in ihe line plantation areas were much more serious. In contrast with this, in the forest which received heavy thinning, most of the Cedro young trees planted in 1984 were heavily auacked in the following succesive two years. Growth rate of the young Meliaceae plants in the lightly-thinned forest was almost the same to that in the line plan­ tation area in the first year, but it reduced consider­ ably in the second year. In the heavily-thinned forest, on the other hand, new growth was vigorous. With a view to reducing the damages of young Meliaceae caused by Hypsipyla, regenera1ion of Au&. SliJH . Oct. Nov. D~ c.. J:111. Feb. Ma,. Mo,uh Meliaccae under the canopy of other trees is expect­ ed to be effective. Particularly, Caoba would grow Fig. 2. Seasonal pancrns of the rates of high enough to escape from the attack of Hypsipyla the infested trees (•). 1he newly under the canopy, providing ihat iis growth rate is sprouted trees (• ) and the insect not as fast as that in open areas. density (O)

Seasonal changes of tree damages and increase of Hypsipy/a density and the damage ratio Hypsipyla populat ion density of host planis. In plantation areas, the damage ratio of Cedro and A survey was carried out in the experimental rield Caoba started increasing from the beginning of the which had been grown to Cedro seedlings after clear­ rainy season, usually September (Fig. 3). It reached culling to analyze 1he rela1ionships of the infesta­ 1he maximum level in October resulting from ac­ tion level in the host plant and the density of cumulated reproduction, thereafter it gradually Hypsipyla with availability of its oviposition sites, decreased by the end of the rainy season. During i.e. newly sprouted trees. The investigation was made the dry season, the population density was main­ during the period the end of the dry season to the tained generally at a low level. However, it some­ end of the rainy season (Fig. 2). In September when times increased to some extent due to the occasional a rainy season started, the first peak of new sprout­ rainfall for a short period, thereby another small ing came out, accompanying an increasing popula­ peak of infestation was induced in a year. The tion density of Hypsipyla as well as a rapid expansion damages in Cedro were always greater 1han in Caoba of damaged trees. In addition to the close correla­ tl1roughoui the year. tion between the seasonal changes of Hypsipyla ln regard to the interaction bet ween the popula­ densities and the damage ratios throughout the period tion density of H. grandello and its host species, it up to March, both of these changes were also clo·sely might be explained as follows: correlated to the change of the number of newly (I) At the beginning of the rainy season, 1he host sprouted trees from August to December, but not trees are in ideal conditions for Hypsipyla thereafter up to March (Fig. 2). In the latter half to increase its density. of the rainy season, another great increase of newly (2) During the rainy season. the oviposition sites sprouted trees did not induce the corresponding arc abundantly available, but the infestation 154 JARQ 24(2) 1990

e .

. O• - 800 • - .

" . ------~ f re . ~\ ~ - - - - ~ I 0 - - • 14 ~ ~ L ~ - ~ - A - 10 111 200 ~ - , ), - ... t a .. ~ '· .. ~ le ; • ~ _, r>.. -~ .. ,.IP ' le r. .~ ,..., - It .... rl~ ... le; , , ' . 11.hY-~ . . . Jan. Mrir. May Jul. Sept. Nov. hn. Mar. May Jul. Sept. Nov. Jan. M.r. May Jul. Sc1>1. Nov. 1986 1987 1988

Fig. 3. Seasonal pancrns of damage rates in plam number of the hoStS: Ccdro (0 ) and Caoba (• )

level decreases because or the possible high Kobayashi, F. and Dr. Kobayashi, K. for their mortality or larvae and the less opportunity guidance in implementing the present study. or mating caused by continuous and heavy rainralls. (3) During the dry season, the infestation level References is basically maintained in low level, since l) Com111011wcahh Agricultural Burea11x ( I 980): Distri­ oviposition sites arc not sufficient enough be­ bution maps of pests. Series A (Agriculture), Map no. cause or limited rainrall. 447, 448, London. 2) Dubois, J. L. C. ( 1971}: Silvicultural research in the Recommendation Amazon. National rorcs1ry school Curitiba, Brazil (FAO). 3) Gray, 8. (1972): Economic tropical forest entomology. Various approaches have been proposed in the past A1111. Rev. £11101110/., 11 , 313-354. to solve the problems relating 10 Hypsipyla. They 4) Grijpma, P. (1970): Immunity of Too110 iliata var. include biological control by parasites and microbes, austmlis Md Klwya ivore11sis to attacks of Hypsipyla chemical control using insecticides, bio-chemical con­ gr,mdella Zeller in Turrialba, Costa Rica. T11rrialba. trol by manipulating adult behaviors, sterile 20, 85-93. 3 1 5) Grijprna, A. & Gara, R. I. (1970): Studies on the male method, and silvicultural method • 1 >. The shoot borer Hypsipyla grandella Zeller. I. Host selec­ above result of the present study suggests that plan­ tion behavior. Turrialba, 20, 233-240. tation under the canopy with an adequate ar1ercare 6) J ICA (1979) : Report on preliminary survey or the possibly be errective for Meliaceae species 10 grow forest development cooperation in the Republic or without heavy auacks by Hypsipyla grandella. Peru, Tokyo. 7) Kobayashi, r., Yamazaki, S. & Ikeda, T. (1986) : Hypsipyla grandell,1 threatening Mcliaccae plantations The authors express hearty thanks 10 Mrs. Sonia, in Peruvian Amazon. In Proceedings of 18th IUFRO S. T., Mr. Koike, 1-1. and Mr. lizuka, K. for theiir World Congress Division IL, 146- 153. cooperation, and also to Dr. Matsui, M., Dr. 8) Kokubo, J. (1979): Damage and control of the 155

mahogany shoot borer. Forest Pests, 28(7), 7-10 (In ceac en turrialba, Costa Rica. Studies on the shoot Japanese]. borer Hypsipylo grondella (Zeller) Lep. vol . 9) Matsui, M. (1986): Regeneration trial in Peruv:ian Ill. (ed. J . L. Whitmore), CATIE Misc. Pub. I, Amazon. Tropical Forestry, 6, 14-18 (In Japanese]. 97-103. 10) Nickle, W. R. & Grijpma, P. (1974): Studies on [ he 12) Yamazaki, S. (1987): Serious damage of mahogany shoot-borer Hypsipyla gmndella (Zeller) (Lcp., Pyral­ by a shoot borer, Hypsipyla grandello Zeller (Lepidop­ idae). XXV. Hexamermis albicans Siebold (Nema.10- tera, Pyralidac). Tropical Forestry, 8, 26-34 {In da, Mermithidac) a parasite of the larva. T11rrialb<1, Japanese]. 24, 222- 226. 11) Sannchei, J.C., Hosten, E. H. & Whicmore, J. L. (Received for publica1ion, Scp1. 7, 1989) (1976): Componamientode cinco especies de Melia-