Evaluation of Cover Crops and Biopesticides to Manage Meloidogyne incognita on Sweetpotatoes in Greenhouse and Microplot Settings

Figure 1:

Effect of winter and summer cover crops on plant growth and Meloidogyne incognita race 3 reproduction in the greenhouse_

Winter cover crop	Root fresh weight (g)	Shoot fresh weight (g)	Biomassa (g)	Meloidogyne incognita eggs/g rootb	Reproductive factorc
Fallow	0 cd	0 d	0 d	0 b	0.2
Black oats	141 ab	26 b	167 ab	105 b	1.6
Crimson clover	16 c	13 c	29 d	1,834 b	5.0
Daikon radish	76 bc	45 a	121 bc	79 b	1.0
Elbon rye	166 a	16 d	182 ab	48 b	1.1
Field peas	24 c	17 c	41 cd	5,430 a	15.3
Wheat	145 ab	18 c	162 ab	160 b	2.5
Yellow mustard	36 c	29 b	65 cd	352 b	1.5
Mix 1e	171 a	29 b	200 a	51 b	1.1
Mix 2f	170 a	21 bc	191 ab	62 b	1.0
P valueg	0.0001****	0.0001****	0.0001****	0.0001****
Summer cover crop
Fallow	0 c	0 d	0 c	0 b	0.002
Elbon rye	182 ab	30 c	213 ab	288 a	0.058
Piper sudangrass	244 a	58 ab	303 a	176 ab	0.035
Sunn hemp	130 b	50 b	181 b	23 ab	0.005
Velvetbean	101 b	70 a	171 b	18 b	0.004
P valueg	0.0001****	0.0001****	0.0001****	0.0136**

Meloidogyne incognita race 3 reproduction and sweetpotato yield following winter cover crops in a microplot setting_

Winter cover crop	Winter cover crop biomassa (g)	April M. incognita/100cm3 soil	July M. incognita/100cm3 soil	September M. incognita/100cm3 soil	Sweetpotato yield (kg/plant)
Fallow	18 db	30 ab	421 a	470 a	0.90 a
Black oats	51 bcd	22 dc	305 a	333 a	1.43 a
Crimson clover	44 bcd	19 dc	570 a	407 a	0.92 a
Daikon radish	32 dc	17 d	282 a	437 a	1.36 a
Elbon rye	70 abc	18 d	330 a	317 a	1.30 a
Field peas	97 a	35 a	416 a	385 a	1.05 a
Yellow mustard	27 d	26 bc	879 a	507 a	1.10 a
Mix 1c	84 ab	21 dc	393 a	317 a	1.38 a
P valued	0.0001****	0.0001****	0.0661*	0.0001****	0.2458

Effect of biopesticides on Meloidogyne incognita race 3 reproduction and sweetpotato yield in a microplot setting_

	Biopesticide		M. incognita/100 cm3 soil	Marketable yield/plant (kg)
Name	Active ingredient	Rate
Untreated	None	None	1,236 aa	0.509 a
AzaGuard	Azadirachtin	1.1 L/ha	1,082 c	0.513 a
BoteGHA ES	Beauveria bassiana	2.3 L/ha	1,190 ab	0.442 a
BotaniGard 22WP + Triple Threat Entomopathogenic Nematodes	Beauveria bassiana + Steinernema feltiae, Steinernema carpocapsae, Heterorhabditis bacteriophora	4.9 kg/ha + 123.5 million IJ’s/ha	773 f	0.533 a
Chitocide	Quillaja extract and chitosan	1.2 kg/ha	819 e	0.558 a
Majestene	Heat-killed Burkholderia spp.	18.7 L/ha	1,043 c	0.505 a
MeloCon	Purpureocillium lilacinum	0.7 L/ha	765 f	0.378 a
Minuet	Bacillus subtilis	1.5 L/ha	881 d	0.460 a
Monterey Nematode Control	Saponins of Quillaja saponaria	2.5 L/ha	920 d	0.367 a
Promax	Thyme oil	12.4 L/ha	834 e	0.432 a
Seduce	Spinosad	33.6 kg/ha	819 e	0.418 a
Velum	Fluopyram	0.4 L/ha	1,159 b	0.517 a
P valueb			0.0001****	0.9743

Effect of biopesticides on sweetpotato plant growth parameters and Meloidogyne incognita race 3 nematode reproduction when grown in the greenhouse_

Biological control			Root fresh weight (g)	Shoot fresh weight (g)	Biomassa (g)	M incognita eggs/root system	M. incognita eggs/g rootb
Name	Active ingredient	Rate
Untreated	None	None	36 ac	35 a	71 a	114,778 ab	3,607 ab
AzaGuard	Azadirachtin	1.1 L/ha	37 a	32 a	69 a	83,183 ab	2,316 ab
BotaniGard 22 WP + Triple Threat Entomopathogenic Nematodes	Beauveria bassiana + Steinernema feltiae, Steinernema carpocapsae, Heterorhabditis bacteriophora	2.3 L/ha	39 a	31 a	70 a	151,634 a	5,180 a
BoteGHA ES	Beauveria bassiana	4.9 kg/ha + 123.5 million IJ’s/ha	42 a	37 a	80 a	121,832 ab	3,039 ab
Chitocide	Quillaja extract and chitosan	1.2 kg/ha	43 a	31 a	74 a	97,874 ab	2,817 ab
Majestene	Heat-killed Burkholderia spp.	18.7 L/ha	37 a	35 a	76 a	129,140 ab	4,657 a
MeloCon	Purpureocillium lilacinum	0.7 L/ha	40 a	35 a	75 a	73,018 ab	2,086 ab
Minuet	Bacillus subtilis	1.5 L/ha	39 a	33 a	72 a	96,509 ab	2,813 ab
Monterey Nematode Control	Saponins of Quillaja saponaria	2.5 L/ha	37 a	35 a	73 a	132,973 ab	4,189 ab
Promax	Thyme oil	12.4 L/ha	42 a	35 a	77 a	134,160 a	3,929 ab
Seduce	Spinosad	33.6 kg/ha	49 a	34 a	84 a	117,961 ab	2,806 ab
Velum	Fluopyram	0.4 L/ha	43 a	33 a	72 a	7,563 b	194 b
P valued			0.2123	0.9370	0.7363	0.0239**	0.0375**