THE ERROR INVOLVED IN SUBSAMPLING OF LARGE LIGHT TRAP CATCHES OF INSECTS = L'ERREUR IMPLIQUEE DANS LE SOUS-ECHANTILLONNAGE DES CAPTURES D'INSECTES DANS LES GRANDS PIEGES LUMINEUXVAN ARK H.1975; PHYTOPHYLACTICA; AFR. S.; DA. 1975; VOL. 7; NO 1; PP. 1-7; ABS. AFRIKAANS FR.; BIBL. 13 REF.Article

ON CERTAIN MACROCLIMATIC FACTORS, DIELDRIN COVERSPRAYING AND NIGHT-FLYING INSECTS = FACTEURS MACROCLIMATIQUES, PULVERISATION DE DIELDRINE ET INSECTES A VOL NOCTURNEVAN ARK H.1975; PHYTOPHYLACTICA; AFR. S.; DA. 1975; VOL. 7; NO 1; PP. 59-64; ABS. AFRIKAANS FR.; BIBL. 1 P. 1/2Article

L'INFLUENCE DE LA LUTTE CONTRE HOTODERMES MOSSAMBICUS SUR LA CULTURE DE COUVERTURE DANS LA REGION DE SAVANE BOISEE DU NORD DU TRANSVAALPRETORIUS LM; VAN ARK H.1972; PHYTOPHYLACTICA; AFR. S.; DA. 1972; VOL. 4; NO 2; PP. 45-49; ABS. ANGL. FR.; BIBL. 8 REF.Serial Issue

A FURTHER EXPERIMENT ON THE EFFECT OF DIELDRIN COVERS PRAYS ON WOOD-EATING TERMITES = NOUVEAUX ESSAIS PORTANT SUR L'EFFET DE LA DIELDRINE EN PULVERISATION DE COUVERTURE SUR LES TERMITES XYLOPHAGESVAN ARK H; SHEASBY JL.1972; PHYTOPHYLACTICA; AFR. S.; DA. 1972; VOL. 4; NO 3; PP. 79-86; ABS. AFRIKAANS FR.; BIBL. 4 REF.Serial Issue

Introduction to sequential sampling as well as optimum sample sizeVAN ARK, H.1984, Num 194, 9 p.Serial Issue

RESISTANCE OF CITRUS RED SCALE, AONIDIELLA AURANTII (MASK.), TO INSECTICIDESNEL JJC; DE LANGE L; VAN ARK H et al.1979; J. ENTOMOL. SOC. SOUTH. AFR.; ISSN 0013-8789; ZAF; DA. 1979; VOL. 42; NO 2; PP. 275-281; BIBL. 6 REF.; 1 ILL.Article

ON THE POSSIBLE DEVELOPMENT OF RESISTANCE TO ENDOSULFAN BY AMERICAN BOLLWORM ON COTTON.BASSON NCJ; VAN ARK H; VAN DEN BERG A et al.1979; J. ENTOMOL. SOC. SOUTH AFR.; ISSN 0013-8789; ZAF; DA. 1979; VOL. 42; NO 1; PP. 61-64; BIBL. 8 REF.Article

RESIDUES IN SHEEP EXPOSED TO BHC TREATED KAROO VELD IN THE OUTBREAK REGION OF THE BROWN LOCUST (LOCUSTANA PARDALINA (WALKER)) = RESIDUS CHEZ LES MOUTONS VIVANT SUR LE VELD DU KAROO TRAITE AU HCH DANS LA REGION GREGARIGENE DU CRIQUET BRUN (L.P. WALKER)BOTHA DH; ROSS WF; VAN ARK H et al.1974; PHYTOPHYLACTICA; AFR. S.; DA. 1974; VOL. 6; NO 4; PP. 235-247; ABS. AFRIKAANS FR.; BIBL. 12 REF.Article

THE EFFECT OF DIELDRIN COVERSPRAYING ON SOME SOUTH AFRICAN SPIDERS AND SCORPIONSDIPPENAAR SCHOEMAN AS; DE L GENIS N; VAN ARK H et al.1978; PHYTOPHYLACTICA; ZAF; DA. 1978; VOL. 10; NO 4; PP. 115-122; ABS. DUT/FRE; BIBL. 20 REF.Article

Further insecticide trials for the control of Cactoblastis cactorum (Lepidoptera: Pyralidae) as well as Dactylopius opuntiae (Hemiptera: Dactylopiidae) on spineless cactusPRETORIUS, M.W; VAN ARK, H.Phytophylactica. 1992, Vol 24, Num 3, pp 229-233, issn 0370-1263Article

Insecticide trials for the control of Cactoblastis cactorum (Lepidoptera: Pyralidae) on spineless cactusPRETORIUS, M. W; VAN ARK, H; SMIT, C et al.Phytophylactica. 1986, Vol 18, Num 3, pp 121-125, issn 0370-1263Article

Preliminary mound-fumigation trials for the control of Trinervitermes trinervoides colomies (Isoptera: Termitidae)PRETORIUS, M.W; VAN ARK, H; MÖHR, J.D et al.Phytophylactica. 1991, Vol 23, Num 1, pp 89-90, issn 0370-1263, 2 p.Article

The effect of bollworm control with regard to populations of spider mites and some of their natural enemies on cottonBOTHA, J. H; VAN ARK, H; SCHOLTZ, A. J et al.Phytophylactica. 1986, Vol 18, Num 3, pp 141-150, issn 0370-1263Article

Reciprocal differences in intraspecies crosses of tobacco (Nicotiana tabacum L.)VAN HEERDEN, H. G; LAMPRECHT, M. P; VAN ARK, H et al.South African journal of plant and soil. 1988, Vol 5, Num 3, pp 117-119, issn 0257-1862Article

High yields of cytoplasts from protoplasts of Lolium perenne and Beta vulgaris gradient centrifugationVAN ARK, H. F; HALL, R. D; CREEMERS-MOLENAAR, J et al.Plant cell, tissue and organ culture. 1992, Vol 31, Num 3, pp 223-232, issn 0167-6857Article

Improvement of the tissue culture response of seed-derived callus cultures of Poa pratensis L. : effect of gelling agent and abscisic acidVAN ARK, H. F; ZAAL, M. A. C. M; CREEMERS-MOLENAAR, J et al.Plant cell, tissue and organ culture. 1991, Vol 27, Num 3, pp 275-280, issn 0167-6857Article