Wilps, H. et al. (1996): Testing new products - Summary report on the field research in Mauritania, 1993-199...

go to previous section of this publication

2 Activities carried out and results

2.1 Testing new products and methods

Of the three representative IGRs selected, triflumuron (Alsystin, Bayer Co., Leverkusen) was tested most intensively, since this product was effective at lower concentrations than teflubenzuron (Nomolt, Shell Corp.) and diflubenzuron (Dimilin, Duphar) (about 1/3 lower amounts of active ingredients required). As botanicals, we selected neem oil from India (SROM Co.) (largely standardised; readily available in amounts of up to 10,000 litres and more, while being relatively economical at <6 US $/l), as well as M. volkensii powder with constant content of active ingredient. The experiments with Metarhizium flavoviride spores against hopper bands were performed in collaboration with the IITA, DFPV.

2.1.1 Effectiveness tests on insect growth regulators (IGRs), botanicals and fungal spores

The IGRs and botanicals used gave dose-dependent mortality rates of 80 - 100 % after 6 - 12 days. Fairly comparable mortality rates were also achieved with the fungal spores, but in this case more than I2 days were required for effectiveness. The most important mortality rates obtained for larvae and adults during the period of the project are summarised in Tables 1 and 2.

Tab. 1 Mortality rates (in %) of S. gregaria adults (field cage trials)

Products	Class	Dosage	Highest mortality (in %)
			1991/1992 after		1992/1993 after
			6 days	12 days	6 days	12 days
Neem oil	Botanicals	1 g a.i./ha	88	92	38	95
Azal-F		1 g a.i./ha	62	80	-	-
Melia volkensii		10 g a.i./ha	-	-	32	88
Metarhizium flavoviride	Mycocides	10¹³ spores/ha	0	88	-	95
Beauveria		10¹³ spores/ha	20	50	-	-
bassiana		2.5x10¹³ spores/ha	-	-	33	88
Triflumuron	Benzoyl phenyl	25 g a.i./ha	-	-	25	70
Teflubenzuron	ureas (BPU)	50 g a.i./ha	48 (1990)	69 (1990)	30	65

Tab. 2 Mortality rate (in %) of S. gregaria larvae

			Highest mortality in %
			1991/92 after		1992/93 after		1993/1994 after		1994/95 after
Products	Class	Dosage	6 days	12 days	6 days	12 days	6 days	10 days	6 days	12 days
Neem oil	Botanicals	0.8 - 2.4 g a.i./ha	38	90	33	60	80	85	38	56
Neem Azal		1 g a.i./ha	50	94	-	-	45	78	-	-
Melia volkensii		10 g a.i./ha	-	-	10	50¹	42	66	46	91
Nosema locustae	Microbial pesticides	baits	0 (1990)	0 (1990)	-	-	-	-	-	-
Beauveria bassiana		2.5x10¹³	-	-	42	66	-	-	-	-
Metarhizium flavoviride			-	-	-	-	50	92	47	98
Triflumuron	Benzoyl phenyl ureas	12.5 g a.i./ha	-	-	48	72	-	-	-	-
		25 g a.i./ha	70	100	43²	70²	40³	60 - 70³	75⁵	100⁵
		50 g a.i./ha	-	-	60	100	-	80⁴	40⁶	93⁶
Teflubenzuron		25 g a.i./ha	40	81	-	-	-	-	-	-
		50 g a.i./ha	-	-	72	82	-	-	-	-
Diflubenzuron		60 g a.i./ha	-	-	-	-	-	-	44	73

In all tests, the mortality rate for untreated controls was <10 %, and for the controls treated with solvent alone <22 %. Source of the products: Neem oils (Prof. Schmutterer, Univ. Giessen; Trifolio Co., Lahnau; SROM Corp., India); M. volkensii extracts (Prof. Rembold, MPI Munich; Prof. Mwangi, Univ. Nairobi); benzoyl phenyl ureas (Bayer Corp., Leverkusen; Shell, Inc., Ingelheim; and Rhône-Poulenc Co.); mycocides (Dr. Prior, IIBC; Dr. Crawford, Myco Tech Co.; Dr. Welling, BBA).
1. M. volkensii treated larvae did not undergo adult moulting
2 Topical application infield-cage trials
3 Topical application on a hopper band
4 Barrier application
5 Topical application on sleeping places
6 Barrier treatment
The amounts applied for barrier treatments varied between 0.12 and 0.16l/ha

go to next section of this publication