Effect of sulphur foliar applications on the tomato-potato psyllid (Bactericera cockerelli) in a potato crop

Figures & data

Table 1 Insecticide treatments for control of tomato-potato psyllid (TPP) in a main crop potato trial at Pukekohe Research Station, 2012–2013 season.

Spray date	Treatment 1 ‘Sulphur only’	Treatment 2 ‘Sulphur/Insecticide A’	Treatment 3 ‘Sulphur/Insecticide B’	Treatment 4 ‘Standard insecticide programme’
29 November	Sulphur + Contact Xcel	Sulphur + Contact Xcel	Sulphur + Contact Xcel	Abamectin + Eco-oil
5 December	Sulphur + Contact Xcel	Sulphur + Contact Xcel	Sulphur + Contact Xcel	Abamectin + Eco-oil
12 December	Sulphur + Contact Xcel	Spiromesifen + Contact Xcel + sulphur	Sulphur + Contact Xcel	Abamectin + Eco-oil
19 December	Sulphur + Contact Xcel	Spiromesifen + Contact Xcel + sulphur	Sulphur + Contact Xcel	Spirotetramat + Partner
28 December	Sulphur + Contact Xcel	Sulphur + Contact Xcel	Spiromesifen + Contact Xcel + sulphur	Spirotetramat + Partner
4 January	Sulphur + Contact Xcel	Sulphur + Contact Xcel	Spiromesifen + Contact Xcel + sulphur	Spirotetramat + Partner
10 January	Sulphur + Contact Xcel	Spinetoram + Bond Xtra + sulphur	Sulphur + Contact Xcel	Spinetoram + Bond Xtra
19 January	Sulphur + Contact Xcel	Spinetoram + Bond Xtra + sulphur	Sulphur + Contact Xcel	Spinetoram + Bond Xtra
25 January	Sulphur + Contact Xcel	Sulphur + Contact Xcel	Spinetoram + Bond Xtra + sulphur	Spinetoram + Bond Xtra
31 January	Sulphur + Contact Xcel	Sulphur + Contact Xcel	Spinetoram + Bond Xtra + sulphur	Spinetoram + Bond Xtra
7 February	Sulphur + Contact Xcel	Methamidiphos + Contact Xcel + sulphur	Sulphur + Contact Xcel	Lambda-cyhalothrin + Contact Xcel
14 February	Sulphur + Contact Xcel	Methamidiphos + Contact Xcel + sulphur	Sulphur + Contact Xcel	Lambda-cyhalothrin + Contact Xcel
22 February	Sulphur + Contact Xcel	Sulphur + Contact Xcel	Methamidiphos + Contact Xcel + sulphur	Lambda-cyhalothrin + Contact Xcel
28 February	Sulphur + Contact Xcel	Sulphur + Contact Xcel	Methamidiphos + Contact Xcel + sulphur	Methamidiphos + Contact Xcel
7 March	Methamidiphos + Contact Xcel + sulphur	Methamidiphos + Contact Xcel + sulphur	Methamidiphos + Contact Xcel + Sulphur	Methamidiphos + Contact Xcel
14 March	Methamidiphos + Contact Xcel + sulphur	Methamidiphos + Contact Xcel + sulphur	Methamidiphos + Contact Xcel + sulphur	Methamidiphos + Contact Xcel

Insecticides and adjuvant rates:

1. Sulphur (Kumulus® DF; BASF NZ Ltd) at 6 kg/ha.

2. Abamectin (18 g/L) (Avid®; Syngenta Crop Protection Ltd, NZ) at 800 mL/ha.

3. Lambda-cyhalothrin (250 g/L) (Karate® Zeon; Syngenta Crop Protection Ltd, NZ) at 120 mL/ha.

4. Spirotetramat (150 g/L) (Movento®; Bayer CropScience, NZ) at 350 mL/ha.

5. Spiromesifen (240 g/L) (Oberon®; Bayer CropScience, NZ) at 600 mL/ha.

6. Spinetoram (120 g/L) (Sparta®; Dow Agrosciences Ltd, NZ) at 500 mL/ha.

7. Methamidophos (600 g/L) (Tamaron®; Bayer CropScience, NZ) at 1000 mL/ha.

8. Contact™Xcel (non-ionic adjuvant; NuFarm Ltd, NZ) at 100 mL/ha.

9. Eco-oil® ([852 g/L] canola oil; Organic Crop Protectants Pty Ltd, NZ) at 2 mL/L of tank mix.

10. Partner® (esterified vegetable oil; Bayer CropScience, NZ) at 2 L/ha.

11. Bond® Xtra (organosilicone/latex polymer adjuvant; Etec Crop Solutions Ltd, NZ).

Table 2 Effect of spray treatments on tomato-potato psyllid (TPP) nymph numbers in potato foliage (mean number of nymphs per middle plant height compound leaf). Within an assessment date, means with the same letter are not significantly (P < 0.05) different.

	22 Jan	30 Jan	5 Feb	12 Feb	20 Feb	27 Feb	5 Mar	13 Mar
Sulphur only	1.05 a	0.10 b	0.39 b	0.51 b	0.29 b	1.08 b	2.74 b	6.50 b
Sulphur/insecticide A	0 a	0 a	0.12 b	0 a	0.02 a	0.01 a	0.04 a	0.07 a
Sulphur/insecticide B	0 a	0 a	0.05 a	0.03 a	0.02 a	0 a	0 a	0 a
Standard insecticide programme	0 a	0 a	0 a	0 a	0.01 a	0.01 a	0.03 a	0 a

Average level treatment (3 df) < 0.001.

Change over time time (7 df) < 0.001.

Time × treatment (21 df) < 0.001.

Table 3 Summary of the number of foliar-applied conventional insecticide applications, average marketable and reject tuber yields (kg/plot), and tuber specific gravity of harvested potatoes following different spray regimes in a main crop spring/summer trial at Pukekohe during 2012–2013. See Table 1 for details of each treatment.

Treatment	Number of insecticide applications	Marketable tuber yield (kg/plot)	Reject tuber weight (kg/plot)	Specific gravity of marketable tubers
Sulphur only	2	30.7^a	5.43	1.057
Sulphur/insecticide A	8	38.7^b	5.86	1.066
Sulphur/insecticide B	8	40.0^b	4.29	1.067
Standard insecticide programme	16	37.8^b	4.00	1.074
ANOVA P value (for differences between sulphur and/or insecticide treatments)		0.001	0.138	0.080
LSD		6.4	1.86	0.012

Means with the same letter are not significantly (P < 0.05) different.

Table 4 Summary of number of foliar-applied conventional insecticide applications, and zebra chip (ZC) incidence (%), ZC score (scale 0–9) and ZC severity (score > 4) of harvested potatoes following different spray regimes in a main crop spring/summer trial at Pukekohe during 2012–2013. See Table 1 for details of each treatment.

		Marketable tubers			Reject tubers
Treatment	Number of insecticide applications	ZC incidence (%)	Mean ZC score	ZC score > 4	ZC incidence (%)	Mean ZC score	ZC score > 4
Sulphur only	2	41.5^b	1.94^a	20.5^a	39.5^a	2.30^a	27.0^a
Sulphur/insecticide A	8	48.5^b	3.42^a	44.5^a	41.0^a	2.90^a	35.0^a
Sulphur/insecticide B	8	38.5^b	2.35^a	28.0^a	43.5^a	2.85^a	36.5^a
Standard insecticide programme	16	27.5^b	1.71^a	24.0^a	22.0^a	1.26^a	14.5^a
ANOVA P value (for differences between sulphur and/or insecticide treatments)		0.793	0.651	0.610	0.337	0.436	0.469
LSD		38.2	3.45	35.2	23.2	2.57	28.0

Means with the same letter are not significantly (P < 0.05) different.